solution

In a normal Q-Q plot, we expect to see data points line up to form a straight line when they are random samples from a normal distribution. As in almost all statistical rules, this expectation is literally an “expectation” or what we expect to see on average. When the sample size of the data is small, a normal Q-Q plot may not entirely resemble a straight line even when the data points are truly random samples from a normal distribution. Use my.qqnorm (rnorm (20)) repeatedly to draw several normal Q-Q plots, each using 20 random numbers drawn from the standard normal distribution to see the likely departure from a straight line.