Releveling factors in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to change the reference level of the factor to "B".

R Programming

f <- factor(c("A", "B", "C"))
f <- relevel(f, ref = [1])
levels(f)

Drag options to blanks, or click blank then click option'

A"B"

B"C"

C"A"

D"D"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a level name that does not exist in the factor.

Forgetting to put the level name inside quotes.

The relevel() function changes the reference level of a factor. Here, setting ref = "B" makes "B" the first level.

2fill in blank

medium

Complete the code to set the reference level of the factor colors to "green".

R Programming

colors <- factor(c("red", "green", "blue"))
colors <- relevel(colors, ref = [1])
levels(colors)

Drag options to blanks, or click blank then click option'

A"red"

B"green"

C"blue"

D"yellow"

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a level not present in the factor.

Not assigning the result back to the variable.

Setting ref = "green" makes "green" the reference level in the factor colors.

3fill in blank

hard

Fix the error in the code to correctly relevel the factor f to have "low" as the reference level.

R Programming

f <- factor(c("high", "medium", "low"))
f <- relevel(f, ref = [1])
levels(f)

Drag options to blanks, or click blank then click option'

A"low"

Blow

C'low'

Dlow"

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around the level name.

Using mismatched or incomplete quotes.

The reference level must be a string enclosed in double quotes. Using "low" is correct.

4fill in blank

hard

Fill both blanks to create a factor f from vals and relevel it to have "second" as the reference level.

R Programming

vals <- c("first", "second", "third")
f <- factor([1])
f <- relevel(f, ref = [2])
levels(f)

Drag options to blanks, or click blank then click option'

Avals

B"first"

C"second"

Dc("first", "second", "third")

Attempts:

3 left

💡 Hint

Common Mistakes

Creating the factor from a wrong vector or literal.

Setting a reference level not present in the factor.

Use the vector vals to create the factor, then set the reference level to "second".

5fill in blank

hard

Fill all three blanks to create a factor f from data, relevel it to "C", and then get the levels.

R Programming

data <- c("A", "B", "C", "A")
f <- factor([1])
f <- relevel(f, ref = [2])
result <- levels([3])

Drag options to blanks, or click blank then click option'

Adata

B"C"

Cf

D"B"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names in any of the steps.

Setting a reference level not in the factor.

Create the factor from data, set "C" as the reference level, and get the levels of f.