Q-Q plot

During the interview, you can use a Q-Q plot to support the result of the Shapiro-Wilk test.

A Q-Q plot that compares a certain sample data against the values of a normal distribution helps to assess the normality of the sample visually.

Recall that:

qqplot(x, y) - produces a Q-Q plot of two datasets,
qqnorm(x) - produces a Q-Q plot against normal distribution.

The line added by qqline(x) is by default normal.

The cats dataset from the MASS package is available for this exercise.

Question

Which of the below sentences about the Q-Q plot is true?

Possible answers

A point on the plot corresponds to one of the quantiles of the second distribution plotted against the same quantile of the first distribution.

A Q-Q plot is a graphical method for comparing two probability distributions by plotting their quantiles against each other.

If the two distributions being compared are similar, the points will approximately lie on the line.

All of the above answers are true.

Exercise

Q-Q plot

Instructions 1/3

Question

Possible answers