If you have no experience with probability plots, it can be helpful to look at several sample data sets that actually do come from a normal distribution. Use software to draw several random samples of the same size from an actual normal population and create normal probability plots. These plots can be compared to the normal probability plot from the actual data. If the real data plot looks similar to the plots where you know that the population is normal, then your data are consistent with the null hypothesis (i. e., the data came from a normal population). If the real data plot is “extreme” (quite different from the plots coming from a normal population), then the differences are not likely due to chance and you can reject the hypothesis that the data came from a normal population.
a. Create a normal probability plot of the residuals of the Games1 data from Question 26.
b. Use software to draw a random sample of n = 40 from an actual normal probability distribution with mean 0 and standard deviation 1. Create a normal probability plot of the sample data.