Suppose we tested n diseased people. Compute x2 as a function of n. Does it increase proportionally to the sample size?
The significance of deviations from the null hypothesis depends on the sample size. Conduct a x2 test for the following samples based on Example 8.7.1. Suppose that 20% of diseased people tested have a particular allele (this would, of course, vary in a series of real experiments), and that 13% of healthy people are known to have the allele.