Solar keratoses are skin lesions commonly found on the scalp, face, backs of hands, forearms, ears, scalp, and neck. They are caused by long-term sun exposure, but they are not skin cancers. Chen et al.

(A-24) studied 39 subjects randomly assigned (with a 3 to 1 ratio) to imiquimod cream and a control cream. The criterion for effectiveness was having 75 percent or more of the lesion area cleared after 14 weeks of treatment. There were 21 successes among 29 imiquimod-treated subjects and three successes among 10 subjects using the control cream. The researchers used Fisher’s exact test and obtained a p value of .027. What are the variables involved? Are the variables quantitative or qualitative? What null and alternative hypotheses are appropriate? What are your conclusions?