Knowledge Quiz: Factors

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Consider the factor f1 generated by the following code.

v1 <- sample(1:3, 10, TRUE)
f1 <- factor(v1, levels = 1:3, labels = 3:1)

What will the expression levels(f1) return?

The character vector: "3", "2", "1"The character vector: "1", "2", "3"The numeric vector: 3, 2, 1The numeric vector: 1, 2, 3The numeric vector: 3A length-10 numeric vector containing some combination of the values: 1, 2, 3.A length-10 character vector containing some combination of the values: "1", "2", "3".A length-10 factor containing some combination of the values: 1, 2, 3.

• Correct
• Wrong: This vector is ordered incorrectly.
• Wrong: Factor level names are always character values.
• Wrong: Factor level names are always character values (these numbers are also ordered incorrectly).
• Wrong: This is the number of levels, nlevels(f1).
• Wrong: f1 has ten elements, but it has only three levels.
• Wrong: f1 has ten elements, but it has only three levels.
• Wrong: f1 has ten elements, but it has only three levels.