Introduction to R

How do you create a variable named x with the numeric value 5?

• x : 5

• x <- 5

• int x = 5

The value of a string variable can be surrounded by single quotes.

• True

• False

The following values: 10.5, 55 and 787, belongs to which data type?

• Integer
• numeric

• Boolean

All elements of an atomic vector can be of different types.

• True
• False
• Depends on the vector
• Not sure

You can construct a list using c( )

• True

• False

• Not sure

Matrices and arrays are created with matrix( ) and array( ), or by using the assignment form of dim( )

• True

• False

• Not sure

Consider the R code below, what is the type of vector a:

a <- c("r", 1)

• numeric

• character

• logical

• Integer

Which of the type of data structures below is not homogeneous?

• atomic vector

• matrix

• array

• list

A data frame is a list of equal-length vectors.

• True
• False
• Depends on the programming language

Consider the R code below. How many factor levels are there?

(x <- factor(c("a","b","b","a","c")))

• 1

• 2

• 3