Multiple Choices: Vectors

Questions

1. What function is commonly used to create a sequence of numbers in a vector? ::: {.cell}

seq() c() repeat() paste()

2. Which function combines multiple values into a single vector in R?

list() combine() c() vector()

3. What will be the output of the following code: c(1, 2, 3) + c(4, 5, 6)?

c(5, 7, 9) c(4, 5, 6, 1, 2, 3) c(4, 7, 10) Error

4. Which function is used to determine the type of elements in a vector?

typeof() class() is.vector() mode()

5. What will be the output of length(c(10, 20, 30, 40))?

10 4 3 40

6. If x <- c(5, 10, 15, 20, 25), what is the output of x[2]?

5 10 15 20

7. What is the result of sum(c(2, 4, 6, 8, 10))?

20 30 25 40

8. Which of the following functions will check if an object is a vector?

is.vector() is.numeric() is.factor() is.character()

9. What will be the result of c(1, 2, 3) * 2?

c(1, 2, 3, 2, 4, 6) c(1, 4, 9) c(2, 4, 6) Error

10. If y <- c("apple", "banana", "cherry"), what is the result of y[2:3]?

apple banana c(“banana”, “cherry”) cherry

11. What is the output of the following code: rep(1, times = 5)?

c(1, 2, 3, 4, 5) c(1, 1, 1, 1, 1) c(5, 5, 5, 5, 5) c(1, 2, 1, 2, 1)

12. What does the function mean() do when applied to a numeric vector?

Calculates the sum of all elements Calculates the product of all elements Calculates the average of all elements Calculates the length of the vector

13. What will be the output of c(1, 2, 3) > 2?

TRUE FALSE c(TRUE, FALSE, FALSE) c(FALSE, FALSE, TRUE)

14. Which function would you use to remove duplicate elements from a vector in R?

distinct() unique() remove() omit()

15. If z <- c(1, 2, NA, 4), what will be the result of mean(z, na.rm = TRUE)?

2.5 7 3 NA

16. Which operator will concatenate two vectors in R?

+ c() concat() append()

17. What will be the output of c(TRUE, FALSE, TRUE) & c(TRUE, TRUE, FALSE)?

c(TRUE, FALSE, FALSE) c(TRUE, TRUE, FALSE) c(FALSE, TRUE, TRUE) c(FALSE, FALSE, FALSE)

18. What does sum(c(TRUE, FALSE, TRUE, FALSE, TRUE)) return?

5 3 2 ERROR

19. Which function would you use to reverse the order of elements in a vector?

rev() flip() reverse() order()

20. If x <- c(3, 6, 9, 12, 15), what does x[x > 9] return?

c(3, 6, 9) c(9, 12, 15) c(12, 15) c(12, 15)

21. What is the result of c(1, "2", 3) in R?

c(1, 2, 3) c(“1”, “2”, “3”) c(1, “2”) Error

22. Which function would you use to repeat each element of a vector a specified number of times?

repeat() rep() duplicate() recycle()

23. What will x[1:3] <- c(10, 20, 30) do to x <- c(1, 2, 3, 4, 5)?

Replace elements at indices 1, 2, and 3 with 10, 20, 30 Add 10, 20, 30 to elements at indices 1, 2, and 3 Remove elements at indices 1, 2, and 3 Error

24. What will the expression 1:5 * 2 return?

c(2, 4, 6, 8, 10) c(1, 3, 5, 7, 9) c(3, 6, 9, 12, 15) Error

25. What is the output of which(c(FALSE, TRUE, FALSE, TRUE))?

c(TRUE, FALSE, TRUE, FALSE) c(2, 4) c(1, 3) c(FALSE, TRUE, FALSE, TRUE)

26. What will be the output of any(c(FALSE, FALSE, TRUE))?

TRUE FALSE NA Error

27. What will x <- c(5, 10, 15); y <- x * x > 25 set y to?

c(25, 100, 225) c(TRUE, TRUE, TRUE) c(FALSE, TRUE, TRUE) c(FALSE, FALSE, TRUE)

28. What is the result of c(1, 2, NA, 4) == NA in R?

TRUE FALSE NA c(FALSE, FALSE, NA, FALSE)

29. Which function would you use to sort a vector in ascending order?

order() sort() rank() arrange()

30. If z <- c("a", "b", "c", "d"), what does z[c(FALSE, TRUE, TRUE, FALSE)] return?

c(“a”, “d”) c(“b”, “c”) c(“c”, “d”) c(“a”, “b”)

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