Unit 2- R programming MCQs Quiz

What is the difference between a scalar and a vector in R?

• A vector is a single-number variable, while a scalar is a variable that holds multiple numbers.

• A scalar and a vector are the same thing in R.

• A scalar is a single-number variable, whereas a vector is considered a different variable type that can hold multiple elements.

• R doesn't have a concept of scalars, only vectors.

What are the R variable types called?

• Classes

• Modes

• Types

• Forms

Which of the following is NOT a valid mode for an R vector?

• Integer

• Character

• Logical

• Object

How are vectors stored in R, similar to arrays in C?

• Randomly

• Contiguously

• In a linked list

• In a hash table

What happens when you try to insert or delete elements from a vector after it's been created?

• R automatically resizes the vector.

• It's not possible, as the size is determined at creation.

• You can, but it requires a special function.

• R throws an error.

If x <- c(88, 5, 12, 13), what is the result of x <- c(x[1:3], 168, x[4])?

• c(88, 5, 12, 13, 168)

• c(168, 88, 5, 12, 13)

• c(88, 5, 12, 168, 13)

• c(88, 5, 168, 12, 13)

What function is used to obtain the length of a vector?

• size()

• len()

• length()

• dim()

What is the output of length(x) if x <- c()?

• NULL

• 1

• 0

• An error

What does the expression 1:length(x) return if x <- c()?

• 1 2 3

• 1 0

• NULL

• An error

In R, what are matrices and arrays considered to be?

• Data frames

• Lists

• Vectors

• Scalars