On a test of scholastic ability administered to college students in the United States, the mean is 500 and the standard deviation is 100. Each of the following 95% CIs for the mean of one population was computed from a random sample of students from the university in question: University Y, 601.63–642.75; University Z, 502.42– 534.68. Both universities claim that their students are superior to the national average of 500.

(a) Is this claim correct?

(b) How do these results illustrate the advantages that CIs have over testing a specific null hypothesis, such as whether the population mean is equal to 500?