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R Language - Quiz(MCQ)
1 .
Who is introduced R Programming Language?
A)
Ross Ihaka
B)
Robert Gentleman
C)
Both (A) and (B)
D)
Florian Hahne

Correct Answer :   Both (A) and (B)

Explanation : R is a programming language for statistical computing and graphics supported by the R Core Team and the R Foundation for Statistical Computing. Created by statisticians Ross Ihaka and Robert Gentleman, R is used among data miners, bioinformaticians and statisticians for data analysis and developing statistical software. Users have created packages to augment the functions of the R language.

2 .
When the First appeared R Programming Language?
A)
August 1992
B)
August 1993
C)
August 1994
D)
August 1995

Correct Answer :   August 1993

Explanation : R was initially written by Ross Ihaka and Robert Gentleman at the Department of Statistics of the University of Auckland in Auckland, New Zealand. R made its first appearance in August 1993.

3 .
What is a correct syntax to output "Hello World" in R?
A)
'Hello World'
B)
"Hello World"
C)
print("Hello World")
D)
All of the other answers are correct

Correct Answer :   All of the other answers are correct

4 .
How do you insert COMMENTS in R code?
A)
# This is a comment
B)
/* This is a comment
C)
// This is a comment
D)
None of the above

Correct Answer :   # This is a comment

5 .
How do you create a variable named x with the numeric value 5?
A)
x : 5
B)
x <- 5
C)
int x = 5
D)
All of the above

Correct Answer :   x <- 5

6 .
Which function is often used to concatenate elements?
A)
join()
B)
merge()
C)
paste()
D)
concat()

Correct Answer :   paste()

7 .
Which statement is used to stop a loop?
A)
stop
B)
exit
C)
break
D)
return

Correct Answer :   break

8 .
Which function is used to find the amount of rows and columns in an array?
A)
dim()
B)
nchar()
C)
length()
D)
dim_len()

Correct Answer :   dim()

9 .
How do you start writing a while loop in R?
A)
while x < y:
B)
x < y while
C)
while x < y
D)
while (x < y)

Correct Answer :   while (x < y)

10 .
How do you start writing an if statement in R?
A)
if (x > y)
B)
if x > y:
C)
if x > y then:
D)
None of the above

Correct Answer :   if (x > y)

11 .
Which function is used to add additional columns in a matrix?
A)
add()
B)
cbind()
C)
join()
D)
append_item()

Correct Answer :   cbind()

12 .
Which function is used to draw points (markers) in a diagram?
A)
d()
B)
draw()
C)
plot()
D)
canvas()

Correct Answer :   plot()

13 .
How can you assign the same value to multiple variables in one line?
A)
var1, var2, var3 <- "Orange"
B)
var1, var2, var3 = "Orange"
C)
var1, var2, var3 => "Orange"
D)
var1 <- var2 <- var3 <- "Orange"

Correct Answer :   var1 <- var2 <- var3 <- "Orange"

14 .
Which operator is used to add together two values?
A)
The & sign
B)
The + sign
C)
The * sign
D)
None of the above

Correct Answer :   The + sign

15 .
The following values: 10.5, 55 and 787, belongs to which data type?
A)
numeric
B)
integer
C)
complex
D)
All of the above

Correct Answer :   numeric

16 .
R allows integration with the procedures written in the?
A)
C
B)
Ruby
C)
Java
D)
Basic

Correct Answer :   C

Explanation : R allows integration with the procedures written in the C, C++, .Net, Python or FORTRAN languages for efficiency.

17 .
R is free software distributed under a GNU-style copy left, and an official part of the GNU project called?
A)
GNU A
B)
GNU L
C)
GNU S
D)
GNU R

Correct Answer :   GNU S

Explanation : R is free software distributed under a GNU-style copy left, and an official part of the GNU project called GNU S.

18 .
Which of the following is true about R?
A)
R has an effective data handling and storage facility
B)
R is a well-developed, simple and effective programming language
C)
R provides a large, coherent and integrated collection of tools for data analysis.
D)
All of the above

Correct Answer :   All of the above

19 .
Command lines entered at the console are limited to about ________ bytes
A)
4090
B)
4095
C)
4120
D)
4225

Correct Answer :   4095

Explanation : Elementary commands can be grouped together into one compound expression by braces (‘{’ and ‘}’).

20 .
R language is a dialect of which of the following languages?
A)
C
B)
S
C)
SAS
D)
Matlab

Correct Answer :   S

Explanation : The R language is a dialect of S which was designed in the 1980s. Since the early 90’s the life of the S language has gone down a rather winding path. The scoping rules for R are the main feature that makes it different from the original S language.

21 .
How many atomic vector types does R have?
A)
6
B)
5
C)
4
D)
3

Correct Answer :   6

Explanation : R language has 6 atomic data types. They are logical, integer, real, complex, string (or character) and raw. There is also a class for “raw” objects, but they are not commonly used directly in data analysis.

22 .
Which operator can be used to compare two values?
A)
=
B)
<>
C)
==
D)
><

Correct Answer :   ==

23 .
Which function can be used to return the square root of a number?
A)
sr()
B)
sqroot()
C)
sqrt()
D)
square_root()

Correct Answer :   sqrt()

24 .
What will the following function do with the str string: nchar(str)
A)
Add spaces to each word inside the str string
B)
Insert an escape character before the str string
C)
Add a new line for each word inside the str string
D)
Find the number of characters in the str string

Correct Answer :   Find the number of characters in the str string

25 .
How do you create a function in R?
A)
my_function <- function.
B)
my_function <- function()
C)
my_function <- function[]
D)
None of the above

Correct Answer :   my_function <- function()

26 .
How do you call a function in R?
A)
my_function()
B)
my_function;
C)
my_function[]
D)
(my_function);

Correct Answer :   my_function()

27 .
Which function can be used to create a data frame?
A)
df()
B)
dframe()
C)
dataframe()
D)
data.frame()

Correct Answer :   data.frame()

28 .
What is the correct way to create a list of strings?
A)
fruits <- v("banana", "apple", "orange")
B)
fruits <- c("banana", "apple", "orange")
C)
fruits <- list("banana", "apple", "orange")
D)
fruits <- vectorOf("banana", "apple", "orange")

Correct Answer :   fruits <- list("banana", "apple", "orange")

29 .
What is the correct way to create a vector of strings?
A)
fruits <- v("banana", "apple", "orange")
B)
fruits <- c("banana", "apple", "orange")
C)
fruits <- list("banana", "apple", "orange")
D)
fruits <- listOf("banana", "apple", "orange")

Correct Answer :   fruits <- c("banana", "apple", "orange")

30 .
Consider the following code: for (x 1:10). Which keyword is missing inside the for loop to output the numbers 1 to 10?
A)
in
B)
seq
C)
list
D)
inside

Correct Answer :   in

31 .
A ______ is a variable that holds one value at a time.
A)
High
B)
Vector
C)
Duplex
D)
Scalar variable

Correct Answer :   Scalar variable

Explanation : A scalar variable was a variable which holds one value at a time. It is a single component which assumes a range of number or string values. A scalar value is associated with every point in space.

32 .
Which function is used to automatically vectorize?
A)
mapply()
B)
lapply()
C)
happly()
D)
kapply()

Correct Answer :   mapply()

Explanation : The mapply() function can be used to automatically “vectorize” a function. What this means is that it can be used to take a function that typically only takes single arguments and create a new function that can take vector arguments.

33 .
R has many functions regarding ________
A)
Distributions, Physics
B)
Probability, Microbiology
C)
Statistics, Probability, Distributions
D)
Statistics, Biotechnology

Correct Answer :   Statistics, Probability, Distributions

Explanation : R has many functions for all types of mathematical objects. For example, Statistics, Probability, Distributions like Multivariate, Continuous, Simple, Discrete etc.

34 .
What will be the output of the following R code?
> x <- 1
> print(x)
A)
1
B)
2
C)
3
D)
4

Correct Answer :   1

Explaination : When a complete expression is entered at the prompt, it is evaluated and the result of the evaluated expression is returned.

35 .
Which of the R following code is example of explicit printing?
A)
> x <- 5 
> x
B)
> x <- 5 
> print(x)
C)
> x <- "auto" 
> x
D)
> x <- "auto" 
> x <- "auto"

Correct Answer :   

> x <- 5 
> print(x)

Explaination : Print command is used for outputting the value.

36 .
If commands are stored in an external file, say commands.R in the working directory work, they may be executed at any time in an R session with the command _____
A)
exect(“command.R”)
B)
exec(“commands.R”)
C)
execute(“commands.R”)
D)
source(“commands.R”)

Correct Answer :   source(“commands.R”)

Explanation : For Windows, Source is also available on the File menu.

37 .
_______ will divert all subsequent output from the console to an external file.
A)
div
B)
sink
C)
exc
D)
exp

Correct Answer :   sink

Explanation : sink() restores it to the console once again.

38 .
Collection of objects currently stored in R is called as _______
A)
list
B)
task
C)
workspace
D)
package

Correct Answer :   workspace

Explanation : All objects created during an R session can be stored permanently in a file for use in future R sessions.

39 .
What is the meaning of the following R function?
x <- c(4, 5, 1, 2, 3, 3, 4, 4, 5, 6)
x <- as.factor(x)
A)
x becomes a factor
B)
x is a factor
C)
x is not a vector
D)
x does not exist

Correct Answer :   x becomes a factor

Explaination : Factors are used to represent categorical data and can unordered and ordered. One can think of a factor as an integer vector where each integer has a label. Factors are important in statistical modelling and are treated specially by modelling functions like lm() and glm().

40 .
What will be the output of the following R function?
paste("Everybody", "is", “a” , "warrior")​
A)
Everybody is a warrior
B)
“Everybody is a warrior”
C)
Everybody”, “is”, “a” , “warrior
D)
“Everybody”, “is”, “a” , “warrior”

Correct Answer :   “Everybody is a warrior”

Explaination : Both paste() and cat() print out text to the console by combining multiple character vectors together, it is impossible for those functions to know in advance how many character vectors will be passed to the function by the user.

41 .
What will be the output of the following R function?
cat("Everybody", "is", "a", “warrior”,sep="*")
A)
Everybody*is*a*warrior
B)
“Everybody*is*a*warrior”
C)
Everybody”, “is”, “a” , “warrior
D)
“Everybody”, “is”, “a” , “warrior”

Correct Answer :   Everybody*is*a*warrior

Explaination : Both paste() and cat() print out text to the console by combining multiple character vectors together, it is impossible to those functions to know in advance how many character vectors will be passed to the function by the user.

42 .
What will be the output of the following R function?
Sys.Date()
A)
Some date
B)
Yesterday date
C)
Present date
D)
Tomorrow date

Correct Answer :   Present date

Explaination : Sys.time and also Sys.Date returns the system’s idea of the current date with and without time. Sys.time returns an absolute date-time value which can be converted to various time zones and may return different days. Sys.Date returns the current day in the current time zone.

43 .
What will be the output of the following R function?
Sys.time()
A)
Some date
B)
Yesterday date and time
C)
Tomorrow date and time
D)
Present date and time

Correct Answer :   Present date and time

Explaination : Sys.time returns a present date-time value which can be converted to various time zones and may return different days. Sys.time and also Sys.Date returns the system’s idea of the current date with and without time.

44 .
R has how many atomic classes of objects?
A)
5
B)
4
C)
3
D)
2

Correct Answer :   5

Explanation : The most basic type of R object is a vector.

45 .
Numbers in R are generally treated as _______ precision real numbers.
A)
real
B)
single
C)
double
D)
imaginary

Correct Answer :   double

Explanation : This means that even if you see a number like “1” or “2” in R, which you might think of as integers, they are likely represented behind the scenes as numeric objects something like “1.00” or “2.00”.

46 .
Attributes of an object (if any) can be accessed using the ______ function.
A)
obj()
B)
attrib()
C)
objects()
D)
attributes()

Correct Answer :   attributes()

Explanation : Not all R objects contain attributes, in which case the attributes() function returns NULL.

47 .
The ________ function can be used to create vectors of objects by concatenating things together.
A)
c()
B)
cp()
C)
con()
D)
concat()

Correct Answer :   c()

Explanation : The simplest such structure is the numeric vector, which is a single entity consisting of an ordered collection of numbers.

48 .
What will be the output of the following R code?
> x <- vector("numeric", length = 10)
> x
A)
01
B)
0 0 0 0 0 0 0 0 0 0
C)
10
D)
00120

Correct Answer :   0 0 0 0 0 0 0 0 0 0

Explaination : You can also use the vector() function to initialize vectors.

49 .
What will be the output of the following R code?
> x <- 6
> class(x)
A)
“real”
B)
“integer”
C)
“imaginary”
D)
“numeric”

Correct Answer :   “numeric”

Explaination : class is used to determine data type of the variable.

50 .
What will be the output of the following R code?
 > sqrt(-17)
A)
NaN
B)
3.67
C)
4.02
D)
-4.02

Correct Answer :   NaN

Explaination : These metadata can be very useful in that they help to describe the object.

51 .
Which of the following code constructs vector of length 11?
A)
> v <- 2*x + y + 4
B)
> v <- 3*x + y + 1
C)
> v <- 2*x + y + 1
D)
> v <- 3*x + y + 2

Correct Answer :   > v <- 2*x + y + 1

Explanation : The elementary arithmetic operators are the usual +, -, *, / and ^ for raising to a power.

52 .
_______ function returns a vector of the same size as x with the elements arranged in increasing order.
A)
orderby()
B)
sort()
C)
orderasc()
D)
sequence()

Correct Answer :   sort()

Explanation : There are other more flexible sorting facilities available like order() or sort.list() which produce a permutation to do the sorting.

53 .
Which of the following statement would print “0” “1” “2” “3” “4” “5” “6” for the following R code?
 > x <- 0:6
A)
as.num(y)
B)
as.logical(x)
C)
as.numeric(x)
D)
as.character(x)

Correct Answer :   as.character(x)

Explaination : as.character would print number from 0 to 6.

54 .
Which of the following is invalid assignment in R?
A)
> m <- mat(nrow = 2, ncol = 3)
B)
> m <- mat(nrow = 2, ncol = 5)
C)
> m <- matrix(nrow = 2, ncol = 3)
D)
> m <- matrix(nrow = 2, ncol = 3.5)

Correct Answer :   > m <- matrix(nrow = 2, ncol = 3)

Explanation : Matrix Entries can be thought of starting in the “upper left” corner and running down the columns.

55 .
What will be the output of the following R code?
> m <- matrix(nrow = 2, ncol = 3)
 > dim(m)
A)
2 2
B)
2 3
C)
3 2
D)
4 5

Correct Answer :   2 3

Explaination : Matrices are constructed column-wise.

56 .
What will be the output of the following R code?
> m <- matrix(1:6, nrow = 2, ncol = 3)
> m
A)
[,1] [,2] [,3]
[1,] 1 3 5
[2,] 2 4 6
B)
[,0] [,1] [,2]
[1,] 1 3 5
[2,] 2 4 6
C)
[,1] [,2] [,3]
[1,] 1 3 6
[2,] 2 4 5
D)
[,5] [,6] [,7]
[1,] 1 3 6
[2,] 2 4 5

Correct Answer :   

[,1] [,2] [,3]
[1,] 1 3 5
[2,] 2 4 6

Explaination : Matrices can also be created directly from vectors by adding a dimension attribute.

57 .
What will be the output of the following R code?
> m <- 1:10
> m
A)
10 9 8 6 5 4 2 3 1 2
B)
0 1 2 3 4 5 6 7 8 9 10
C)
1 2 3 4 5 6 7 8 9 10
D)
1 2 3 4 5 6 7 8 9 10 11

Correct Answer :   1 2 3 4 5 6 7 8 9 10

Explaination : Matrices can be created by column-binding.

58 .
Find the following type of vector?
a <- c(1,2,5.3,6,-2,4)
A)
Integer
B)
Numeric
C)
Logical
D)
Character

Correct Answer :   Numeric

Explaination : The labels are always character irrespective of whether it is numeric or character and also Boolean etc. on the input vector. The nlevels functions will give the count of levels. Factors are created using the factor() function.

59 .
All columns in a matrix must have the same mode and the _________ length.
A)
Same
B)
Different
C)
May be the same
D)
May be different

Correct Answer :   Same

Explanation : All columns in a matrix must have the same mode(numeric, character, etc) and also the same length. byrow=TRUE indicates that the matrix should be filled by rows. byrow=FALSE indicates that the matrix should be filled by columns (the default).

60 .
______ are similar to matrices but can have more than two dimensions.
A)
Columns
B)
Functions
C)
Packages
D)
Arrays

Correct Answer :   Arrays

Explanation : Arrays are similar to matrices which can have more than two dimensions. See help(array) for details. Factors are created using the factor() function. We can Identify elements of a list using the [[]] convention.

61 .
An ordered collection of objects or components are called ________
A)
Datasets
B)
Lists
C)
Databases
D)
Data frames

Correct Answer :   Lists

Explanation : An ordered collection of objects are called lists. A list allows you to gather a variety of (possibly unrelated) objects under one name. We can Identify elements of a list using the [[]] convention.

62 .
The ________ stores the nominal values as a vector of integers in the range of 1 to unique values in the nominal variable.
A)
Lists
B)
Factor
C)
Matrix
D)
Functions

Correct Answer :   Factor

Explanation : The factor stores the nominal values as a vector of integers in the range [1… k] (where k is the no. of unique values of the nominal variable), and an internal vector of character strings (the original values) mapped to these integers.

63 .
On what basis of a variable, OS allocates memory and decides what can be stored in the reserved memory?
A)
Lists
B)
Data sets
C)
Data bases
D)
Data types

Correct Answer :   Data types

Explanation : Based on the data type of a variable, the OS allocates the memory and decides what can be stored on the reserved memory. This means that when you create a variable you reserve some space in memory.

64 .
Which function takes a dim attribute which creates the required number of dimensions?
A)
Array
B)
Lists
C)
Matrix
D)
Vector

Correct Answer :   Array

Explanation : The array function takes a dim attribute which creates the required number of dimensions. While matrices are confined to two dimensions, arrays could be of any number of dimensions.

65 .
Factors are created using the _______ function.
A)
C()
B)
Lists()
C)
Function()
D)
Array()

Correct Answer :   Function()

Explanation : Factors are created using the factor() function. The labels are always character irrespective of whether it is numeric or character or also Boolean etc. in the vector. The nlevels functions will give the count of levels.

66 .
Data frames can have additional attributes such as __________
A)
R.names()
B)
D.names()
C)
Rowname()
D)
Rownames()

Correct Answer :   Rownames()

Explanation : Data frames can have additional attributes such as rownames(), which can be useful for annotating data, like subject_id or sample_id. But most of the time they are not used. A data frame is an important data type in R.

67 .
The four most frequently used types of data objects in R are vectors, matrices, data frames and ________
A)
Lists
B)
Function
C)
Interfaces
D)
Packages

Correct Answer :   Lists

Explanation : The four most frequently used types of data objects in R are vectors, matrices, data frames and lists. A list is a generalisation of a vector and represents a collection of data objects.

68 .
The ________ function creates a regular sequence of values to form a vector.
A)
Rep
B)
Seq
C)
Grep
D)
Sequel

Correct Answer :   Seq

Explanation : The rep function replicates elements of vectors. The seq function creates a regular sequence of values to form a vector. The four most frequently used types of data objects in R are vectors, matrices, data frames and lists.

69 .
Which function is used to enter in data at the terminal?
A)
Scnn
B)
Sccn
C)
Scan
D)
Scanned

Correct Answer :   Scan

Explanation : The scan function is used to enter data at the terminal. This is useful for small datasets but tiresome for entering in large datasets.

70 .
To bind a row onto an already existing matrix, the ______ function can be used.
A)
Sbnd
B)
Sbind
C)
Rbind
D)
Gbind

Correct Answer :   Rbind

Explanation : To bind a row onto an already existing matrix, the rbind function can be used. The scan function is used to enter data at the terminal.

71 .
Which of the following is a 3-dimensional dataset?
A)
Iris
B)
Eris
C)
Toris
D)
Iris

Correct Answer :   Iris

Explanation : The iris dataset is a three dimensional dataset. One dimension is represented for each species: Setosa, Versicolor and Virginica.

72 .
Accessing elements is achieved through a process called ________
A)
Outdexing
B)
Indexing
C)
Scrapping
D)
Highlighting

Correct Answer :   Indexing

Explanation : Accessing elements is achieved through a process called indexing. Indexing may be done by a vector of positive integers and negative integers to indicate inclusion.

73 .
Which are indexed by either row or column using a specific name or number?
A)
Data frames
B)
Data
C)
Datasets
D)
Functions

Correct Answer :   Data frames

Explanation : Data frames can be indexed by either row or column using a specific name (that corresponds to either the row or column) or a number.

74 .
What should we use to access elements with a value greater than five?
A)
Interfaces
B)
Packages
C)
Use functions
D)
Subsetting Commands

Correct Answer :   Subsetting Commands

Explanation : To access elements with a value greater than five we can use some subsetting commands and logical operators to produce the desired result.

75 .
Lists can be created using the _______ function.
A)
List
B)
Matrix.li
C)
Matrix.lists
D)
Lists.matric

Correct Answer :   List

Explanation : Lists can be created using the list function. Like data frames, they can incorporate a mixture of modes into the one list and each component can be of a different length or size.

76 .
How can we access the first component of the list?
A)
Tools
B)
Package
C)
Function
D)
Number of the Position

Correct Answer :   Number of the Position

Explanation : There are a number of ways of accessing the first component of a list. We can either access it through the name of that component (if names are assigned) or by using a number corresponding to the position the component.

77 .
The _________ function returns a list of densities (y) corresponding to bin values (x).
A)
Lists
B)
Spline
C)
Locator
D)
Density

Correct Answer :   Spline

Explanation : The spline function returns a list of densities (y) corresponding to bin values (x). These can be passed to the plot routine to produce a line graph of the density.

78 .
Joining two lists can be achieved either using the _________ function.
A)
Join
B)
Delete
C)
Concat
D)
Reduce

Correct Answer :   Concat

Explanation : Joining two lists can be achieved either using the concatenation function or the append function.

79 .
The length of a list is ______ to the number of components in that list.
A)
Equal
B)
Triple
C)
Double
D)
One fourth

Correct Answer :   Equal

Explanation : The length of a list is equal to the number of components in that list. Lists can be created using the list function. Like data frames, they can incorporate a mixture of modes into the one list and each component can be of a different length or size.

80 .
The first component can be accessed using __________ operator.
A)
OR
B)
AND
C)
Intraction
D)
Extraction

Correct Answer :   Extraction

Explanation : There are a number of ways of accessing the first component of a list. We can either access it through the name of that component (if names are assigned) or by using a number corresponding to the position the component corresponds to. The former approach can be performed using subsetting ([[]]) or alternatively, by the extraction operator ($).

81 .
The ________ function takes an arbitrary number of arguments and concatenates them one by one into character strings.
A)
copy()
B)
del()
C)
bind()
D)
paste()

Correct Answer :   copy()

Explanation : Any numbers given among the arguments are coerced into character strings in the evident way, that is, in the same way they would be if they were printed.

82 .
Which of the following is valid assignment in R?
A)
> x <- fact(c("yes", "yes", "no", "yes", "no"))
B)
> x <- factor(c("yes", "yes", "no", "yes", "no"))
C)
> x <- factor(factor("yes", "no", "no", "yes", "no"))
D)
> x <- factor(factor("yes", "yes", "no", "yes", "no"))

Correct Answer :   > x <- factor(c("yes", "yes", "no", "yes", "no"))

Explanation : Factor objects can be created with the factor() function.

83 .
What will be the output of the following R code?
> x <- vector("list", length = 5)
> x
A)
B)
1
C)
4
D)
NULL

Correct Answer :   NULL

Explaination : We can also create an empty list of a pre-specified length with the vector() function.

84 .
What will be the output of the following R code?
> x <- factor(c("yes", "yes", "no", "yes", "no"))
> table(x)
A)
yes no
2 3
B)
no yes
2 3
C)
no yes
2 2
D)
yes yes
6 2

Correct Answer :   

no yes
2 3

Explaination : The order of the levels of a factor can be set using the levels argument to factor().

85 .
What will be the output of the following R code?
> x <- c(1, 2, NaN, NA, 4)
> is.na(x)
A)
FALSE TRUE TRUE TRUE FALSE
B)
TRUE FALSE TRUE TRUE FALSE
C)
FALSE FALSE TRUE TRUE FALSE
D)
TRUE FALSE TRUE FALSE FALSE

Correct Answer :   FALSE FALSE TRUE TRUE FALSE

Explaination : Missing values are denoted by NA or NaN for q undefined mathematical operations.

86 .
Data frames can be converted to a matrix by calling data _______
A)
as.matrix()
B)
as.matr()
C)
as.mat()
D)
as.max()

Correct Answer :   as.matrix()

Explanation : as.matrix() function should be used to coerce a data frame to a matrix.

87 .
What will be the output of the following R code?
> x <- data.frame(foo = 1:4, bar = c(T, T, F, F))
> ncol(x)
A)
2
B)
4
C)
7
D)
9

Correct Answer :   2

Explaination : Data frames are represented as a special type of list where every element of the list has to have the same length.

88 .
What will be the output of the following R code?
> m <- matrix(1:4, nrow = 2, ncol = 2)
> dimnames(m) <- list(c("a", "b"), c("c", "d"))
> m
A)
c d
a 1 3
b 2 4
B)
c d
a 1 2
b 2 3
C)
c d
a 1 3
b 4 2
D)
Error

Correct Answer :   

c d
a 1 3
b 2 4

Explaination : Matrices can have both column and row names.

89 .
Which of the following statement changes column name to h and f?
A)
rownames(m) <- c(“f”, “f”)
B)
rownames(m) <- c(“h”, “f”)
C)
columnnames(m) <- c(“h”, “f”)
D)
colnames(m) <- c(“h”, “f”)

Correct Answer :   colnames(m) <- c(“h”, “f”)

Explanation : Column names and row names can be set separately using the colnames() and rownames() functions.

90 .
Which of the following statement would read file "foo.txt"?
A)
data <- data(“foo.txt”)
B)
data <- read.data(“foo.txt”)
C)
data <- read.table(“foo.txt”)
D)
read.data <- read.table(“foo.txt”)

Correct Answer :   data <- read.table(“foo.txt”)

Explanation : R will automatically skip lines that begin with a #.

91 .
Which of the following is used for reading tabular data?
> y <- data.frame(a = 1, b = "a")
> dput(y, file = "y.R")
> new.y <- dget("y.R")
> new.y
A)
b a
1 a a
B)
a b
1 1 a
C)
a b
2 1 a
D)
a b
1 2 b

Correct Answer :   

a b
1 1 a

Explaination : Multiple objects can be deparsed at once using the dump function and read back in using source.

92 .
Individual R objects can be saved to a file using the _____ function.
A)
Save
B)
Put
C)
Get
D)
save_image

Correct Answer :   Save

Explanation : The key functions for converting R objects into a binary format are save(), save.image(), and serialize().

93 .
Which of the following R statement will save the output to the file for following R code?
> a <- data.frame(x = rnorm(100), y = runif(100))
> b <- c(3, 4.4, 1 / 3)
A)
keep(a, b, file = “mydata.rda”)
B)
keep_image(a, b, file = “mydata.rda”)
C)
save(a, b, file = “mydata.rda”)
D)
save_image(a, b, file = “mydata.rda”)

Correct Answer :   

save(a, b, file = “mydata.rda”)

Explaination : You can save all objects in your workspace using the save.image() function.

94 .
Which of the following statement will load the objects to the file named "mydata.RData"?
A)
put(“mydata.RData”)
B)
load(“mydata.RData”)
C)
save(“mydata.RData”)
D)
loadAll(“mydata.RData”)

Correct Answer :   load(“mydata.RData”)

Explanation : .rda and .RData are fairly common extensions and you may want to use them because they are recognized by other software

95 .
Which of the following R code creates a connection to 'foo.txt'?
A)
open(con, “r”)
B)
ocon(con, “r”)
C)
opencon(con, “r”)
D)
con <- file(“foo.txt”)

Correct Answer :   con <- file(“foo.txt”)

Explanation : Open is used for opening connection to ‘foo.txt’ in read-only mode.

96 .
Which of the following opens connection to gz-compressed text file?
A)
con <- gzfiles(“words.gz”)
B)
con <- gzfile2(“words.gz”)
C)
con <- gzfile(“words.gz”)
D)
con <- gzfiles2(“words.gz”)

Correct Answer :   con <- gzfile(“words.gz”)

Explanation : For more structured text data like CSV files or tab-delimited files, there are other functions like read.csv() or read.table().

97 .
Which of the following code opens a connection to the file foo.txt, reads from it, and closes the connection when its done?
A)
data <- read.csvo(“foo.txt”)
B)
data <- read.csv(“foo.txt”)
C)
data <- getonly.csv(“foo.txt”)
D)
data <- readonly.csv(“foo.txt”)

Correct Answer :   data <- read.csv(“foo.txt”)

Explanation : Connections must be opened, then the are read from or written to, and then they are closed.

98 .
Which of the following extracts first element from the following R vector?
 > x <- c("a", "b", "c", "c", "d", "a")
A)
x[0]
B)
x[1]
C)
x[2]
D)
x[10]

Correct Answer :   x[1]

Explaination : The element which we want to extract will be in the format of variable[index value of the element] in R script.

99 .
Which of the following extracts first four element from the following R vector?
> x <- c("a", "b", "c", "c", "d", "a")
A)
x[1:4]
B)
x[4:3]
C)
x[0:3]
D)
x[0:4]

Correct Answer :   x[1:4]

Explaination : The multiple successive elements which we want to extract will be in the format of variable[index value of the start element:index value of the last element] in R script.

100 .
What will be the output of the following R code?
> x <- matrix(1:6, 2, 3)
> x[1, , drop = FALSE]
A)
[,1] [,2] [,3]
[1,] 2 3 5
B)
[,1] [,2] [,3]
[1,] 1 2 5
C)
[,1] [,2] [,3]
[1,] 1 3 5
D)
Error

Correct Answer :   

[,1] [,2] [,3]
[1,] 1 3 5

Explaination : By default, when a single element of a matrix is retrieved, it is returned as a vector of length 1 rather than a $1\times 1$ matrix.

101 .
Which of the following return a subset of the columns of a data frame?
A)
Select
B)
Get
C)
Set
D)
Retrieve

Correct Answer :   Select

Explanation : One important contribution of the dplyr package is that it provides a “grammar” for data manipulation and for operating on data frames.

102 .
_________ extract a subset of rows from a dataframe based on logical conditions.
A)
set
B)
filter
C)
subset
D)
rename

Correct Answer :   rename

Explanation : rename is used to rename variables in a dataframe.

103 .
_______ add new variables/columns or transform existing variables.
A)
add
B)
apped
C)
mutate
D)
arrange

Correct Answer :   mutate

104 .
The dplyr package can be installed from CRAN using ________
A)
install.packages(“dplyr”)
B)
installed.packages(“dpl”)
C)
installall.packages(“dplyr”)
D)
installed.packages(“dplyr”)

Correct Answer :   install.packages(“dplyr”)

Explanation : After installing the package it is important that you load it into your R session with the library() function.

105 .
The dplyr package can be installed from GitHub using the _______ package.
A)
dev
B)
devdel
C)
devtool
D)
devtools

Correct Answer :   devtools

Explanation : The GitHub repository will usually contain the latest updates to the package and the development version.

106 .
Which of the following is apply function in R?
A)
apply()
B)
tapply()
C)
fapply()
D)
rapply()

Correct Answer :   tapply()

Explanation : Functions can be passed as arguments to other functions.

107 .
Functions are defined using the _________ directive and are stored as R objects.
A)
fun()
B)
funct()
C)
function()
D)
functions()

Correct Answer :   function()

Explanation : In particular, they are R objects of class “function”.

108 .
What will be the output of the following R code?
> f <- function() {
+              ## This is an empty function
+ }
> class(f)
A)
“function”
B)
“class”
C)
“system”
D)
“procedure”

Correct Answer :   “function”

Explaination : Functions have their own class.

109 .
What will be the output of the following R code?
> f <- function(num) {
+ hello <- "Hello, world!\n"
+ for(i in seq_len(num)) {
+                    cat(hello)
+ }
+                    chars <- nchar(hello) * num
+                    chars
+ }
> meaningoflife <- f(3)
> print(meaningoflife)
A)
22
B)
32
C)
42
D)
52

Correct Answer :   32

Explaination : This function returns the total number of characters printed to the console.

110 .
R Commander is used to ___________ in R.
A)
Use data
B)
Export data
C)
Import data
D)
Work on data

Correct Answer :   Import data

Explanation : R Commander is used to import data in R language. To start the R commander GUI, the user should type in the command Rcmdr into the console. There are 3 different types in which data can be imported in R language.

111 .
Two vectors M and N are defined as M <- c(3, 2, 4) and N <- c(1, 2). What will be the output of vector Z that is defined as Z <- M*N.
A)
Z <- (3, 4, 5)
B)
Z <- (3, 2, 4)
C)
Z <- (3, 6, 4)
D)
Z <- (3, 4, 4)

Correct Answer :   Z <- (3, 4, 4)

Explaination : In R language when the vectors have different lengths, the multiplication begins with the smaller vector and continues till all the elements in the larger vector have been multiplied.

112 .
CRAN package ecosystem has more than ______ packages.
A)
6000
B)
7000
C)
8000
D)
9000

Correct Answer :   6000

Explanation : R language has several packages for solving a particular problem. CRAN package ecosystem has more than 6000 packages.

113 .
Which function in R language is used to find out whether the means of 2 groups are equal to each other or not?
A)
f.tests ()
B)
t.tests ()
C)
l.tests ()
D)
None of the above

Correct Answer :   t.tests ()

Explanation :  t.tests () function in R language is used to find out whether the means of 2 groups are equal to each other. It is not used most commonly in R. It is used in some specific conditions.

114 .
_______ is the easiest method for reshaping the data before analysis.
A)
Package
B)
Function
C)
Structure()
D)
Transpose()

Correct Answer :   Transpose()

Explanation : Transpose t () is the easiest method for reshaping the data before analysis. The transpose (reversing rows and columns) is always the simplest method of reshaping a dataset. Use the t() function to transpose a matrix or a data frame.

115 .
_______ function is used to apply an expression for a given dataset.
A)
That()
B)
This()
C)
With()
D)
Unwith()

Correct Answer :   With()

Explanation : With a () function is used to apply an expression for a given dataset. R language has a large number of in-built functions and the user can create their own functions. In R, a function is an object to the R interpreter is able to pass control to the function.

116 .
________ function can be used to add datasets in R provided with the columns in the datasets should be the same.
A)
rbind()
B)
jbind()
C)
bbind()
D)
hbind()

Correct Answer :   rbind()

Explanation : rbind () function can be used add datasets in R language provided the columns in the datasets should be the same. R has a large number of in-built functions and also the user can create their own functions.

117 .
What is the memory limit in R for 64 bit system?
A)
8 TB
B)
10 TB
C)
12 TB
D)
16 TB

Correct Answer :   8 TB

Explanation : 8TB is the memory limit for 64-bit system memory and 3GB is the limit for 32-bit system memory. A solid understanding of R’s memory management will help you predict how much memory you’ll need for a given task.

118 .
What is the memory limit in R for 32 bit system?
A)
11GB
B)
3GB
C)
8 TB
D)
10TB

Correct Answer :   3GB

Explanation : 8TB is the memory limit for 64-bit system memory and 3GB is the limit for 32-bit system memory. A solid understanding of R’s memory management will help you predict how much memory you’ll need for a given task.

119 .
_______ function is used in applying a function each level of factors.
A)
By()
B)
To()
C)
With()
D)
Here()

Correct Answer :   By()

Explanation : BY () function is used for applying a function each level of factors. R has a large number of in-built functions and also user can create their own functions. In R, a function is an object. So the R interpreter is able to pass control to the function.

120 .
How do you create log linear models in R language?
A)
logfn()
B)
loghy()
C)
loglm()
D)
logmn()

Correct Answer :   loglm()

Explanation : loglm is fit log-linear models by iterative proportional scaling. This function provides a front-end of the standard function, loglin, to allow log-linear models to be specified and fitted in a manner similar to that of other fitting functions.

121 .
If the function in a console is.matrix(X) returns true then X can be considered as a _______
A)
Vector
B)
Matrix Vector
C)
Matrix Object
D)
Matrix data object

Correct Answer :   Matrix Object

Explanation : The function call is.matrix(X) returns TRUE then X can be termed as a matrix data object. R has a large number of in-built functions and also the user can create their own functions.

122 .
_______ measures the probability of the binary response variable in R language.
A)
Statistics
B)
Simpler Regression
C)
Multivariate Regression
D)
Logical Regression

Correct Answer :   Logical Regression

Explanation : Logistic regression can be used for this and the function glm () in R language provides this functionality. Logistic regression is a statistical method for analysing a dataset in which there are one or more independent variables which determine an outcome.

123 .
_______ function will measure the probability of the binary response variable in R language.
A)
Jlm()
B)
Glm()
C)
Glmi()
D)
Gelmi()

Correct Answer :   Glm()

Explanation : Glm() in R language provides this functionality. Logistic regression is a statistical method for analysing a dataset in which there are one or more independent variables that determine an outcome.

124 .
________ function can be used to select the random sample of size 'n' from a huge dataset.
A)
Sample()
B)
Simple()
C)
Signal()
D)
While()

Correct Answer :   Sample()

Explanation : Sample() function can be used to select a random sample of size ‘n’ from the huge dataset. R has a large number of in-built functions and also the user can create their own functions.

125 .
Which function is used to select variables and observations from a given dataset?
A)
While()
B)
Signal()
C)
Subset()
D)
Sample()

Correct Answer :   Subset()

Explanation : Subset () function is used to select variables and observations from a given dataset. R has a large number of in-built functions and also the user can create their own functions.

126 .
How will you check if an element is present in a vector?
A)
Match()
B)
Search()
C)
Dismatch()
D)
Mismatch()

Correct Answer :   Match()

Explanation : It can be done using the match () function- match () function returns the first appearance of a particular element. The other way is to use %in% which returns a Boolean value either true or false.

127 .
Warnings are generated by the _________ function.
A)
run()
B)
warning()
C)
error()
D)
message()

Correct Answer :   warning()

Explanation : warning is an indication that something is wrong but not necessarily fatal; execution of the function continues.

128 .
To get the current date, the _______ function will return a Date object which can be converted to a different class if necessary.
A)
Sys.Time
B)
DateTime
C)
Sys.DateTime
D)
Sys.Date

Correct Answer :   Sys.Date

Explanation : The POSIXlt class stores date/time values as a list of components (hour, min, sec, mon, etc.) making it easy to extract these parts.

129 .
What will be the output of the following R code?
> printmessage <- function(x) {
+ if(x > 0)
+         print("x is greater than zero")
+ else
+         print("x is less than or equal to zero")
+ invisible(x)
+ }
> printmessage(NA)
A)
Error
B)
Warning
C)
Messages
D)
Null

Correct Answer :   Error

Explaination : You can’t do that test if x is a NA or NaN value.

130 .
What will be the output of the following R code snippet?
> lm <- function(x) { x * x }
> lm
A)
func(x) { x * x }
B)
function { x $ x }
C)
function(x) { x * x }
D)
function(x) { x / x }

Correct Answer :   function(x) { x * x }

Explaination : When R tries to bind a value to a symbol, it searches through a series of environments to find the appropriate value.

131 .
A function, together with an environment, makes up what is called a ______ closure.
A)
formal
B)
reflective
C)
function
D)
symmetry

Correct Answer :   function

Explanation : The function closure model can be used to create functions that “carry around” data with them.

132 .
The ________ for R are the main feature that make it different from the original S language.
A)
scoping rules
B)
closure rules
C)
environment rules
D)
closure & environment rules

Correct Answer :   scoping rules

Explanation : This function never actually uses the argument b, so calling f(2) will not produce an error because the 2 gets positionally matched to a.

133 .
What will be the output of the following R code snippet?
> g <- function(x) {
+             a <- 3
+             x+a+y
+          ## 'y' is a free variable
+ }
> g(2)
A)
8
B)
9
C)
10
D)
Error

Correct Answer :   Error

Explaination : Object ‘y’ not found error is displayed.

134 .
The _________ function is a kind of "constructor function" that can be used to construct other functions.
A)
keep.pow()
B)
make.pow()
C)
keep.power()
D)
make.power()

Correct Answer :   make.power()

Explanation : Typically, a function is defined in the global environment, so that the values of free variables are just found in the user’s workspace.

135 .
________ loop over a list and evaluate a function on each element.
A)
lapply()
B)
apply()
C)
sapply()
D)
mapply()

Correct Answer :   apply()

Explanation : An auxiliary function split is also useful, particularly in conjunction with lapply.

136 .
_______ function is same as lapply in R.
A)
sapply()
B)
apply()
C)
lapply()
D)
mapply()

Correct Answer :   sapply()

Explanation : lapply tries to simplify the result.

137 .
_______ is used to apply a function over subsets of a vector.
A)
tapply()
B)
lapply()
C)
apply()
D)
mapply()

Correct Answer :   tapply()

Explanation : t in tapply stands for table.

138 .
lappy functions takes _________ arguments in R language.
A)
two
B)
three
C)
four
D)
five

Correct Answer :   four

Explanation : This function takes three arguments: (1) a list X; (2) a function (or the name of a function) FUN; (3) other arguments via its____argument.

139 .
What will be the value of following R expression?
A)
Warning in log(c(-1, 2)): NaNs produced
B)
Error in log(c(-1, 2)): NaNs produced
C)
Message
D)
All of the above

Correct Answer :   Error in log(c(-1, 2)): NaNs produced

Explanation : Warning is produced due to negative values.

140 .
The recover() function will first print out the function call stack when an _______ occurs.
A)
Error
B)
delete
C)
Warning
D)
Messages

Correct Answer :   Error

Explanation : When you choose a frame number, you will be put in the browse and will have the ability to poke around.

141 .
_______ generate random Normal variates with a given mean and standard deviation.
A)
rpois
B)
dnorm
C)
pnorm
D)
rnorm

Correct Answer :   rnorm

Explanation : The “r” function is the one that actually simulates random numbers from that distribution.

142 .
______ evaluate the cumulative distribution function for a Normal distribution.
A)
rpois
B)
rnorm
C)
pnorm
D)
dnorm

Correct Answer :   pnorm

Explanation : p stands for cumulative distribution.

143 .
Which of the following evaluate the Normal probability density (with a given mean/SD) at a point?
A)
rpois
B)
dnorm
C)
rnorm
D)
pnorm

Correct Answer :   dnorm

Explanation : That point can be a vector of points.

144 .
_______ is the most common probability distribution to work with.
A)
Paradox
B)
Gaussian
C)
Simulation
D)
Parametric

Correct Answer :   Gaussian

Explanation : Working with the Normal distributions requires using four functions.

145 .
What will be the output of the following R code?
 > pnorm(2)
A)
0.6772499
B)
0.9772499
C)
1.9772499
D)
2.6772499

Correct Answer :   0.9772499

Explaination : If you wanted to know what was the probability of a random Normal variable of being less than 2, you could use the pnorm() function to do that calculation.

146 .
_______ is a systematic way to examine how much time is spent in different parts of a program.
A)
Profiling
B)
Logging
C)
Monitoring
D)
Debugging

Correct Answer :   Profiling

Explanation : Sometimes profiling becomes necessary as a project grows and layers of code are placed on top of each other.

147 .
R comes with a ________ to help you optimize your code and improve its performance.
A)
profiler
B)
monitor
C)
browser
D)
debugger

Correct Answer :   debugger

Explanation : In general, it’s usually a bad idea to focus on optimizing your code at the very beginning of development.

148 .
The _______ function computes the time (in seconds) needed to execute an expression.
A)
system.deb()
B)
system.timedeb()
C)
system.time()
D)
system.datetime()

Correct Answer :   system.time()

Explanation : They system.time() function takes an arbitrary R expression as input and returns the amount of time taken to evaluate the expression.

149 .
system.time function returns an object of class _______ which contains two useful bits of information.
A)
proc_time
B)
debug_time
C)
date.time_time
D)
procedure_time

Correct Answer :   proc_time

Explanation : if there’s an error, gives the time until the error occurred.

150 .
Parallel processing is done via __________ package can make the elapsed time smaller than the user time.
A)
statistics
B)
parallel
C)
symmetry
D)
distributed

Correct Answer :   parallel

Explanation : When you have multiple processors/- cores/machines working in parallel, the amount of time that the collection of CPUs spends working on a problem is the same as with a single CPU, but because they are operating in parallel, there is a savings in elapsed time.

151 .
You can time ________ expressions by wrapping them in curly braces within the call to system.time().
A)
error
B)
grater
C)
longer
D)
smaller

Correct Answer :   longer

Explanation : If your expression is getting pretty long (more than 2 or 3 lines), it might be better to either break it into smaller pieces or to use the profiler.

152 .
______ grammar makes a clear distinction between your data and what gets displayed on the screen or page.
A)
d3.js
B)
ggplot1
C)
ggplot2
D)
ggplot3

Correct Answer :   ggplot2

Explanation : The emphasis in ggplot2 is reducing the amount of thinking time by making it easier to go from the plot in your brain to the plot on the page.

153 .
Which of the following cuts numeric vector into intervals of equal length?
A)
cut_time
B)
cut_date
C)
cut_number
D)
cut_interval

Correct Answer :   cut_interval

Explanation : cut_number cuts numeric vector into intervals containing equal number of points.

154 .
Which of the following is a plot to investigate the order in which observations were recorded?
A)
ggorder
B)
ggpcp
C)
ggplot
D)
ggsave

Correct Answer :   ggorder

Explanation : ggsave save a ggplot with sensible defaults.

155 .
_______ is used for translating between qplot and base graphics.
A)
translate_qplot_gpl
B)
translate_qplot_base
C)
translate_qplot_lattice
D)
translate_qplot_ggplot

Correct Answer :   translate_qplot_base

Explanation : translate_qplot_gpl is used for translating between qplot and Graphics Production Library (GPL).

156 .
_______ modifies geom/stat aesthetic defaults for future plots.
A)
translate_qplot_gpl
B)
translate_qplot_base
C)
translate_qplot_ggplot
D)
translate_qplot_defaults

Correct Answer :   translate_qplot_defaults

Explanation : translate_qplot_gpl is used for translating between qplot and Graphics Production Library (GPL).

157 .
______ is used to create a plot to illustrate patterns of missing values.
A)
ggpcp
B)
ggmissplot
C)
ggmissing
D)
ggfluctuation

Correct Answer :   ggmissing

Explanation : The missing values plot is a useful tool to get a rapid overview of the number and pattern of missing values in a dataset.

158 .
______ display contours of a 3d surface in 2d.
A)
aes_gem
B)
aes_auto
C)
aes_contour
D)
geom_contour

Correct Answer :   geom_contour

Explanation : A layer specific dataset – only needed if you want to override the plot defaults.

159 .
_____ display a smooth density estimate.
A)
aes_sdensity
B)
geom_density
C)
geom_contour
D)
geom_density2

Correct Answer :   geom_density

Explanation : geom_density display a smooth density estimate. A smooth density estimate calculated by stat_density.

160 .
________ is interval represented by a vertical line, with a point in the middle.
A)
printplot
B)
geom_range
C)
geom_contour
D)
geom_pointrange

Correct Answer :   geom_pointrange

Explanation : autoplot uses ggplot2 to draw a particular plot for an object of a particular class in a single command.

161 .
Which of the following create a set of identity mappings?
A)
ggorder
B)
aes
C)
ggplot
D)
aes_all

Correct Answer :   ggorder

Explanation : Character vector is given for the creation of identity.

162 .
_______ is new package that makes it easy to "tidy" your data.
A)
tidyneat
B)
tidy
C)
tidynr
D)
tidyr

Correct Answer :   tidyneat

Explanation : Tidy data is data that’s easy to work in R.

163 .
Which of the following is complementary to tidyr?
A)
d3lr
B)
geolr
C)
dplyr
D)
gekl2

Correct Answer :   dplyr

Explanation : Its easy to munge with dplyr.

164 .
Which of the following function takes multiple columns?
A)
extract()
B)
gather()
C)
spread()
D)
separate()

Correct Answer :   gather()

Explanation : gather() gathers column into key-value pairs.

165 .
Which of the following d takes two columns and spreads them into multiple columns?
A)
ggplot
B)
printplot
C)
ggmissplot
D)
print.ggplot

Correct Answer :   print.ggplot

Explanation : spread() makes “long” data wide.

166 .
Which of the following is a principle of analytic graphics?
A)
Show box plots (univariate summaries)
B)
Show causality, mechanism, explanation
C)
Don’t plot more than two variables at at time
D)
Make judicious use of color in your scatterplots

Correct Answer :   Show causality, mechanism, explanation

Explanation : Only do what your tools allow you to do.

167 .
Which of the following is true about the base plotting system?
A)
Plots are created and annotated with separate functions
B)
The system is most useful for conditioning plots
C)
Plots are typically created with a single function call
D)
Margins and spacings are adjusted automatically depending on the type of plot and the data

Correct Answer :   Plots are created and annotated with separate functions

Explanation :

Functions like ‘plot’ or ‘hist’ typically create the plot on the graphics device and functions like ‘lines’, ‘text’, or ‘points’ will annotate or add data to the plot.

168 .
Which of the following is an example of a vector graphics device in R?
A)
GIF
B)
PNG
C)
SVG
D)
JPEG

Correct Answer :   SVG

Explanation : SVG stands for scalable vector graphics.

169 .
Bitmapped file formats can be most useful for _______
A)
Plots that may need to be resized
B)
Scatterplots with many many points
C)
Plots that require animation or interactivity
D)
Plots that are not scaled to a specific resolution

Correct Answer :   Scatterplots with many many points

Explanation : Scatterplots would be used frequently for particular dimension.

170 .
Which of the following functions is typically used to add elements to a plot in the base graphics system?
A)
plot()
B)
hist()
C)
lines()
D)
boxplot()

Correct Answer :   boxplot()

Explanation : text() also can be used to add elements to a plot. boxplot() used to add elements to a plot in the base graphics system.

171 .
Which function opens the screen graphics device for the Mac?
A)
png()
B)
pdf()
C)
quartz()
D)
bitmap()

Correct Answer :   quartz()

Explanation : quartz starts a graphics device driver for the Mac.

172 .
What does the 'pch' option to par() control?
A)
the plotting symbol/character in the base graphics system
B)
the line width in the base graphics system
C)
the orientation of the axis labels on the plot
D)
the size of the plotting symbol in a scatterplot

Correct Answer :   the plotting symbol/character in the base graphics system

Explanation : R makes it easy to combine multiple plots into one overall graph, using either the par ( ) or layout( ) function.

173 .
Which of the following code create a n item vector of random normal deviates?
A)
x1 <- c(rnorm(n))
B)
x1 >- c(norm(n))
C)
x1 <- c(snorm(n))
D)
x1 <- c(pnorm(n))

Correct Answer :   x1 <- c(rnorm(n))

Explanation : rnorm generates random deviates.

174 .
Which of the following statement can read csv files?
A)
read.tab(filename,header=TRUE,sep=’,’)
B)
read.tab(filename,header=False,sep=’,’)
C)
read.csv(filename,header=TRUE,sep=’,’)
D)
read.table(filename,header=TRUE,sep=’,’)

Correct Answer :   read.table(filename,header=TRUE,sep=’,’)

Explanation : Each row of the table appears as one line of the file.

175 .
Which of the following statement read a tab or space delimited file?
A)
read.CSV(filename,header=TRUE)
B)
read.table(filename,header=TRUE)
C)
read.table(filename,header=FALSE)
D)
read.tableall(filename,header=TRUE)

Correct Answer :   read.table(filename,header=TRUE)

Explanation : read.csv and read.csv2 are identical to read.table except for the defaults.

176 .
Which of the following statement is another way to get a subset?
A)
sub(dataset,logical)
B)
subcon(dataset,logical)
C)
data.df[data.df=logical]
D)
subsetcon(dataset,logical)

Correct Answer :   data.df[data.df=logical]

Explanation : subset(data.df,select=variables,logical) get those objects from a data frame that meet a criterion.

177 .
Which of the following sort a dataframe by the order of the elements in B?
A)
x[rev(x$B),]
B)
x[order(x$B),]
C)
x[ordersort(x$B),]
D)
x[rev(order(x$B)),]

Correct Answer :   x[rev(order(x$B)),]

Explanation : x[rev(order(x$B)),] sort the dataframe in reverse order.

178 .
________ remove all the variables from the workspace.
A)
rm(list=ls())
B)
ls()
C)
rm(x)
D)
attach(mat)

Correct Answer :   rm(list=ls())

Explanation : attach(mat) make the names of the variables in the matrix or data frame available in the workspace.

179 .
Which of the following is Mac menu command?
A)
browse.works
B)
browse.workspace
C)
browser.workspace
D)
a statistical transformation

Correct Answer :   browse.workspace

Explanation : It is a Mac menu command that creates a window with information about all variables in the workspace.

180 .
Which of the following will reverse the order of values in x?
A)
all(x)
B)
x%in%y
C)
rev(x)
D)
max(x, na.rm=TRUE)

Correct Answer :   rev(x)

Explanation : rev provides a reversed version of its argument.

181 .
Which of the following finds row sums for each level of a grouping variable?
A)
rowMeans(x, na.rm = FALSE, dims = 1)
B)
rowsum(x, group, reorder = TRUE, …)
C)
rowSums (x, na.rm = FALSE, dims = 1)
D)
colMeans(x, na.rm = FALSE, dims = 1)

Correct Answer :   rowMeans(x, na.rm = FALSE, dims = 1)

Explanation : False value leads to unexpected result.

182 .
Which of the following statement applies the function (FUN) to either rows (1) or columns (2) on object X?
A)
col.max(x)
B)
apply(x,1,min)
C)
apply(x,2,max)
D)
apply(X, MARGIN, FUN, …)

Correct Answer :   apply(X, MARGIN, FUN, …)

Explanation : apply(x,2,max) finds the maximum for each column.

183 .
Which of the following statement finds the maximum for each column?
A)
col.max(x)
B)
apply(x,2,max)
C)
which.min(x)
D)
which.max(x)

Correct Answer :   apply(x,2,max)

Explanation : col.max(x) is another way to find which column has the maximum value for each row.

184 .
Which of the following may be used for linear regression?
A)
Solve(A)
B)
X $*$ Y
C)
X %*% Y
D)
Solve(A,B)

Correct Answer :   Solve(A,B)

Explanation : Solve(A,B) implies inverse of A * B.

185 .
Which of the following sets the size of the outer margins for the graph?
A)
par(ask=False)
B)
par(ask=TRUE)
C)
par(omi=c(0,0,1,0) )
D)
par(mfrow=c(nrow,mcol))

Correct Answer :   par(omi=c(0,0,1,0) )

Explanation : par can be used to set or query graphical parameters.

186 .
Which of the following will add the title "R language" to the graph?
A)
title( “R language”)
B)
var(x, na.rm=TRUE)
C)
titleBar( “R language”)
D)
titleAdd( “R language”)

Correct Answer :   title( “R language”)

Explanation : This function can be used to add labels to a plot.

187 .
______ let’s you perform SQL queries on your R data frames.
A)
plyr
B)
daply
C)
sqldf
D)
forecast

Correct Answer :   plyr

Explanation : sqldf uses SQLite syntax. Plyr will split-apply-combine paradigm for R. Forecast is a generic function for forecasting from time series or time series models. The function invokes particular methods which depend on the class of the first argument.

188 .
________ makes it incredibly easy to fit time series models like ARIMA, ARMA, AR, Exponential Smoothing, etc.
A)
stats
B)
plyr
C)
sqldf
D)
forecast

Correct Answer :   forecast

Explanation : Most important feature is the resulting forecast plot.

189 .
Which of the following syntax is used to install forecast package?
A)
install.pack(“forecast”)
B)
install.packages(“forecast”)
C)
install.packages(“cast”)
D)
install.pack(“forecastcast”)

Correct Answer :   install.packages(“forecast”)

Explanation : forecast is used for time series analysis.

190 .
Which of the following is similar to Moment.js?
A)
ploy
B)
stringr
C)
lubridate
D)
forecast

Correct Answer :   lubridate

Explanation : lubridate is one of those magical libraries that just seems to do exactly what you expect it to.

191 .
_____ specializes in converting data from wide to long format.
A)
gcc
B)
gcc2
C)
reshape
D)
reshape2

Correct Answer :   reshape2

Explanation : reshape2 is used in conjunction with ggplot2 and plyr.

192 .
______ is used to convert wide data to long data.
A)
melt
B)
cast
C)
rcast
D)
dcast

Correct Answer :   melt

Explanation : dcast is used to go from long to wide.

193 .
_____ finds K best paths in a given graph.
A)
kcirt
B)
kmap
C)
ktrees
D)
kBestShortestPaths

Correct Answer :   kBestShortestPaths

Explanation : This package provides some routines to conduct the K-adaptive partitioning (kaps) and recursive partitioning (lrtree) for survival data.

194 .
_______ is a package for parsing, applying, and manipulating data cleaning rules
A)
edr
B)
editrules
C)
edrtools
D)
edrGraphicalTools

Correct Answer :   editrules

Explanation : editrules is a package for parsing, applying, and manipulating data cleaning rules. edrGraphicalTools provides tools for dimension reduction methods.

195 .
Which of the following package provide namespace management functions not yet present in base R?
A)
stringr
B)
nbpMatching
C)
namespace
D)
messagewarning

Correct Answer :   namespace

Explanation : The package namespace is one of the most confusing parts of building a package. nbpMatching contains functions for non-bipartite optimal matching.

196 .
Which of the following is used to analyze paleontological time-series?
A)
paleoTS
B)
parfossil
C)
nbpMatching
D)
accelerometry

Correct Answer :   paleoTS

Explanation : This package contains parfossil parallelized functions for palaeoecological and palaeogeographical analysis.

197 .
________ uniforms and customizes plots of packages ggplot2, graphics and lattice.
A)
uniCox
B)
uniPlot
C)
unigraph
D)
unknownR

Correct Answer :   uniPlot

Explanation : uniPlot() allows to change parameters of the packages graphics, lattice and ggplot2 and to make these changes persistent over one R session.

198 .
What will be the output of the following R code?
install.packages(c("devtools", "roxygen2"))
A)
Exits R studio
B)
Develops the tools
C)
Installs the given packages
D)
Nothing happens

Correct Answer :   Installs the given packages

Explaination : Make sure you have the latest version of R and then run the above code to get the packages you’ll need. It installs the given packages. Confirm that you have a recent version of RStudio.

199 .
To start with the new package in RStudio, double-click the pkgname.Rproj file that _______
A)
Exit()
B)
Run()
C)
Delete()
D)
Create()

Correct Answer :   Create()

Explanation : To get started with your new package in RStudio, double-click the pkgname.Rproj file that create() just made. This will open a new RStudio project for your package. Projects are the way to develop packages.

200 .
If you have an existing package that doesn’t have an .Rproj file, you can use devtools for the use_rstudio("_____/to/package") to add it.
A)
Path
B)
Class
C)
Function
D)
Package

Correct Answer :   Path

Explanation : If you have an existing package that doesn’t have an .Rproj file, you can use devtools for the use_rstudio(“path/to/package”) to add it.

201 .
A bundled package is a package that’s been compressed into a ______ file.
A)
Triple
B)
Double
C)
Single
D)
None of the Above

Correct Answer :   Single

Explanation : A bundled package is a package that’s been compressed into a single file. A source package is just a directory with components like R/, DESCRIPTION, and so on.

202 .
_______ are built in R so that you get HTML.
A)
Bignats
B)
Viddnets
C)
Vignettes
D)
Vighnaants

Correct Answer :   Vignettes

Explanation : Vignettes are built for getting the HTML and PDF output instead of Markdown or LaTeX input. A bundled package is a package that’s been compressed into a single file.

203 .
Files listed in the Rbuildignore are not included in the ______
A)
single
B)
bundle
C)
double
D)
source

Correct Answer :   bundle

Explanation : Files listed in the Rbuildignore were not included in the bundle. .Rbuildignore prevents files from the src package and appearing in the bundled package. It allows you to have some extra directories in your source package that will not be included in the package bundle.

204 .
.Rbuildignore prevents files in the ___________ package from appearing in the bundled package.
A)
single
B)
bundle
C)
double
D)
source

Correct Answer :   source

Explanation : .Rbuildignore prevents files from the source package and appearing in the bundled package. It allows to have some extra directories in your source package that will not be included in the package bundle.

205 .
Which of the following finds the position of a quantile in a dataset?
A)
quantile()
B)
rep()
C)
barplot()
D)
barchart()

Correct Answer :   quantile()

Explanation : barplot() produces a bar graph.

206 .
Which of the following function cross-tabulate tables using formulas?
A)
read
B)
stem
C)
table
D)
xtabs

Correct Answer :   read

Explanation : table() list all values of a variable with frequencies.

207 .
Which of the following groups find the correlation matrix?
A)
stem
B)
col.max(x)
C)
factor.model
D)
which.max(x)

Correct Answer :   factor.model

Explanation : factor.congruence is used to find the factor congruence coefficients.

208 .
Which of the following compute proportions from a contingency table?
A)
par()
B)
prop.table()
C)
anova()
D)
mosaicplot()

Correct Answer :   prop.table()

Explanation : par() is used to query and edit graphical settings.

209 .
Which of the following convert a matrix of phi coefficients to polychoric correlations?
A)
phi2poly
B)
poly()
C)
qline()
D)
multi.plot()

Correct Answer :   phi2poly

Explanation : In statistics, polychoric correlation is a technique for estimating the correlation between two theorized normally distributed continuous latent variables, from two observed ordinal variables.

210 .
Which of the following count the number of good cases when doing pairwise analysis?
A)
count() +
B)
count.poly()
C)
anova.para()
D)
count.pairwise

Correct Answer :   count.pairwise

Explanation : Pairwise comparison generally is any process of comparing entities in pairs to judge which of each entity is preferred.

211 .
Which of the following gives the summary of values likes mean etc?
A)
lm
B)
sd
C)
mean
D)
describe

Correct Answer :   lm

Explanation : Describe give means, sd, skew, n, and se.

212 .
What plot(s) are used to view the linear regression?
A)
Box plot
B)
Scatterplot
C)
Density plot
D)
Scatterplot, Boxplot, Density plot

Correct Answer :   Scatterplot, Boxplot, Density plot

Explanation : Each plot has its own importance of highlighting a specific feature. Scatter plot is used to visualise the relationship between the variables, Box plot is used to spot the outliers which effect line of best fit.

213 .
In lm(response ~ terms), terms specification of the form "first*second" is same as __________
A)
first:second
B)
first+second
C)
first+second+first:second
D)
first:second+second:first

Correct Answer :   first+second+first:second

Explanation : A terms specification of the form “first + second” indicates all the terms in first together with all the terms in second with duplicates removed.

214 .
Predicting y for a value of x that's outside the range of values we actually saw for x in the original data is called ________
A)
Polation
B)
Extrapolation
C)
Regression
D)
Intra polation

Correct Answer :   Extrapolation

Explanation : Predicting y for a value of x that is within the interval of points that we saw in the original data is called interpolation. Predicting y for a value of x that’s outside the range of values we actually saw for x in the original data is called extrapolation.

215 .
What is predicting y for a value of x that is within the interval of points that we saw in the original data called?
A)
Intra polation
B)
Polation
C)
Regression
D)
Extrapolation

Correct Answer :   Intra polation

Explanation : Predicting y for a value of x that is within the interval of points that we saw in the original data is called interpolation. Predicting y for a value of x that’s outside the range of values we actually saw for x in the original data is called extrapolation.

216 .
Analysis of variance in short form is?
A)
AVA
B)
ANVA
C)
ANOV
D)
ANOVA

Correct Answer :   ANOVA

Explanation : If the ANOVA test determines that the model explains a significant portion of the variability in the data, then we can consider testing each of the hypotheses and correcting for multiple comparisons.

217 .
_______ is a simple approach to supervised learning. It assumes that the dependence of Y on X1, X2, . . . Xp is linear.
A)
Gradient Descent
B)
Greedy Algorithms
C)
Linear regression
D)
Logistic regression

Correct Answer :   Linear regression

Explanation : Linear regression is a simple approach to supervised learning. It assumes that the dependence of Y on X1, X2, . . . Xp is linear. linear regression is an incredibly powerful tool for analysing data.

218 .
Although it may seem overly simplistic, _______ is extremely useful both conceptually and practically.
A)
Gradient Descent
B)
Linear regression
C)
Greedy algorithms
D)
Logistic regression

Correct Answer :   Linear regression

Explanation : Linear regression is a simple approach to supervised learning. It assumes that the dependence of Y on X1, X2, . . . Xp is linear. linear regression is an incredibly powerful tool for analysing data.

219 .
The sum of squares of the difference between the observations and the line in the horizontal direction in the scatter diagram can be minimized to obtain the estimates is generally called?
A)
Simple Regression
B)
Formal Regression
C)
Cogistic Regression
D)
Reverse Regression Method

Correct Answer :   Reverse Regression Method

Explanation : The sum of squares of the difference between the observations and the line in the horizontal direction in the scatter diagram can be minimized to obtain the estimates of 0 1 β and β. This is generally called a reverse or inverse regression method.

220 .
In order to calculate confidence intervals and hypothesis tests, it is assumed that the errors are independent and normally distributed with mean zero and _______
A)
SD
B)
KNN
C)
Mean
D)
Variance

Correct Answer :   Variance

Explanation : In order to calculate confidence intervals and hypothesis tests, it is assumed that the errors are independent and normally distributed with mean zero and variance.

221 .
When hypothesis tests and confidence limits are to be used, the residuals are assumed to follow the __________distribution.
A)
Normal
B)
Mutual
C)
Formal
D)
Abnormal

Correct Answer :   Normal

Explanation : When hypothesis tests and confidence limits are to be used, the residuals are assumed to follow the normal distribution.

222 .
The IBM _________ analytics appliances combine high-capacity storage for Big Data with a massively-parallel processing platform for high-performance computing.
A)
LityxEQ
B)
Netezza
C)
Watson
D)
InfoSight

Correct Answer :   Watson

Explanation : IBM Watson is a system based on cognitive computing. With the addition of Revolution R Enterprise for IBM Netezza, you can use the power of the R language to build predictive models on Big Data.

223 .
________ is rapidly being adopted for computing descriptive and query types of analytics on Big data.
A)
EDR
B)
Hadoop
C)
Azure
D)
InfoSight

Correct Answer :   Hadoop

Explanation : However, it has a reputation for not being a suitable environment for high performance complex iterative algorithms such as logistic regression, generalized linear models, and decision trees.

224 .
________ is a JavaScript charting library and feature-rich API set that lets you build interactive Flash or HTML5 charts.
A)
Alterian
B)
ZingChart
C)
paleoTS
D)
InstantAtlas

Correct Answer :   ZingChart

Explanation : ZingChart lets you create HTML5 Canvas charts and more.

225 .
________ is proprietary tool for predictive analytics.
A)
R
B)
EDR
C)
SAS
D)
SSAS

Correct Answer :   SAS

Explanation : SAS (Statistical Analysis System) is a software suite developed by SAS Institute for advanced analytics.

226 .
Which of the following involves predicting a categorical response?
A)
Classification
B)
Clustering
C)
Regression
D)
Summarization

Correct Answer :   Classification

Explanation : Classification techniques are widely used in data mining to classify data.

227 .
_____ is simplest class of analytics.
A)
Predictive
B)
Prescriptive
C)
Summarization
D)
Descriptive

Correct Answer :   Descriptive

Explanation : Descriptive is the simplest class of analytics. Predictive analytics can only forecast what might happen in the future because all predictive analytics are probabilistic in nature.