R interview questions part 36
R interview questions part 36
Take as many assements as you can to improve your validate your skill rating
Total Questions: 20
1. 5 Normal random numbers can be generated with rnorm() by setting seed value to :
Correct Answer is : 1
2. _______ function is used to simulate binary random variables.
Correct Answer is : rbinom()
3. Point out the wrong statement :
Correct Answer is : The sample() function draws randomly from a specified set of (scalar) objects allowing you to sample from arbitrary distributions of numbers
4. __________ distribution is commonly used to model data that come in the form of counts.
Correct Answer is : Poisson
5. Which of the following code represents count with mean of 2 ?
Correct Answer is : rpois(10, 2)
6. Which of the following extracts first element from the following vector ? > x <- c("a", "b", "c", "c", "d", "a")
Correct Answer is : x[1].
7. Point out the correct statement :
Correct Answer is : There are three operators that can be used to extract subsets of R objects
8. Which of the following extracts first four element from the following vector ? > x <- c("a", "b", "c", "c", "d", "a")
Correct Answer is : x[1:4].
9. What would be the output of the following code ? > x <- c("a", "b", "c", "c", "d", "a") > x[c(1, 3, 4)]
Correct Answer is : “a” “c” “c”
10. Point out the wrong statement :
Correct Answer is : The $ operator is used to extract elements of a list or a data frame
11. What would be the output of the following code ? > x <- matrix(1:6, 2, 3) > x[1, 2]
Correct Answer is : 3
12. What would be the output of the following code ? > x <- matrix(1:6, 2, 3) > x[1, ]
Correct Answer is : 38355
13. Which of the following code extracts the second column for the following matrix ? > x <- matrix(1:6, 2, 3)
Correct Answer is : x[, 2].
14. Which of the following extracts first element from the following list ? > x <- list(foo = 1:4, bar = 0.6)
Correct Answer is : x[[1]].
15. Point out the correct statement :
Correct Answer is : You can also use the $ operator to extract elements by name
16. What would be the output of the following code ? > x <- list(foo = 1:4, bar = 0.6, baz = "hello") > name <- "foo" > x$name
Correct Answer is :
17. What would be the output of the following code ? > x <- list(foo = 1:4, bar = 0.6, baz = "hello") > name <- "foo" > x[[name]]
Correct Answer is : 1 2 3 4
18. Point out the wrong statement :
Correct Answer is : The $ operator can be used to extract multiple elements from a list
19. What would be the output of the following code ? > x <- list(a = list(10, 12, 14), b = c(3.14, 2.81)) > x[[c(1, 3)]]
Correct Answer is : 14
20. What would be the output of the following code ? > x <- list(aardvark = 1:5) > x$a
Correct Answer is : 1 2 3 4 5
