Control Structures in R Programming MCQ question and answer with solution

61

. . . . . . . . returns TRUE then X can be termed as a matrix data object.

A) is."matrix(X") B) is.matrix(X) C) is.notamatrix(X ) D) is.matrix("X")

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Answer & Solution

Answer: Option B

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62

. . . . . . . . package provides basic functionalities in R environment like arithmetic calculations, input/output.

A) R base B) R boost C) R serve D) R comm

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Answer & Solution

Answer: Option A

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63

What will be the output of the following R code?

> x <- 3
> switch(x, 2+2, mean(1:10), rnorm(5))

A) 2.2903605 2.3271663 -0.7060073 1.3622045 -0.2892720 B) 5.5 C) NULL D) Error

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Answer & Solution

Answer: Option A

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64

What will be the output of the following R code?

> x <- 1:4
> lapply(x, runif)

A)

[[1]]
[1] 0.02778712
[[2]]
[1] 0.5273108 0.8803191
[[3]]
[1] 0.37306337 0.04795913 0.13862825
[[4]]
[1] 0.3214921 0.1548316 0.1322282 0.2213059

B)

[[1]]
[1] 1.02778712
[[2]]
[1] 2.5273108 0.8803191
[[3]]
[1] 3.37306337 0.04795913 0.13862825
[[4]]
[1] 0.3214921 0.1548316 0.1322282 0.2213059

C)

[[1]]
[1] 1.02778712
[[2]]
[1] 0.5273108 0.8803191
[[3]]
[1] 0.37306337 0.04795913 0.13862825
[[4]]
[1] 3.3214921 2.1548316 1.1322282 0.2213059

D) Error

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Answer & Solution

Answer: Option A

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65

What will be the output of the following R code?

> x <- c("a", "b", "c", "d")
> for(i in 1:4) {
    + ## Print out each element of 'x'
    + print(x[i])
+ }

A) [1] "a"
[1] "b"
[1] "c"
[1] "d" B) [1] "c"
[1] "b"
[1] "a"
[1] "d" C) [1] "d"
[1] "c"
[1] "b"
[1] "a" D) Error

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Answer & Solution

Answer: Option A

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66

. . . . . . . . function gives an error message if the desired package cannot be loaded.

A) Dplyr B) Require C) Library D) Sample

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Answer & Solution

Answer: Option C

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67

What will be the output of the following R code?

> x <- list(a = 1:5, b = rnorm(10))
> lapply(x, mean)

A) $a
[1] 3
$b
[1] 0.1322028 B) $a
[1] 4
$b
[1] 0.1322028 C) $a
[1] 5
$b
[1] 0.1322028 D) $a
[2] 5
$b
[1] 3

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Answer & Solution

Answer: Option A

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68

Which of the following R code syntax is syntactically valid?

A)

if ( statement1 ) {
    statement2
} else if ( statement3 ) {
    statement4
} else if ( statement5 ) {
    statement6
} else
    statement8

B)

if ( statement1 ) {
    statement2
} elseif ( statement3 ) {
    statement4
} elseif ( statement5 ) {
    statement6
} else
    statement8

C)

if ( statement1 ) {
    statement2
} elseif ( statement3 ) {
    statement4
} else if ( statement5 ) {
    statement6
} else
    statement8

D)

if ( statement1 ) {
    statement2
} else if ( statement5 ) {
    statement6
} else
    statement8

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Answer & Solution

Answer: Option A

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69

. . . . . . . . function takes various parameters like formula, data, subset, labels, etc.

A) Pears B) Pairs C) Tears D) Cars

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Answer & Solution

Answer: Option B

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70

. . . . . . . . functions can be "built which contain all of the necessary data for evaluating the function.

A) Objective B) reflective C) Nested D) Symmetry

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Answer & Solution

Answer: Option A

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Control Structures in R Programming MCQ question and answer with solution | R Programming MCQs