8.12 For Table 7.3 on the student survey, viewing the table as matched triplets, you can compare the proportion of “yes” responses among alcohol, cigarettes, and marijuana.

a. Construct the marginal distribution for each substance, and find the three sample proportions of “yes” responses.

b. Explain how you could represent the data with a three-way contingency table in order to use a generalized CMH procedure (see Section 6.4.2) to test marginal homogeneity.