Refer to Exercise 9.23. Suppose the researchers conjectured that the new medications caused an increase in fat content and that this increase accumulated as the medication was ­continued in the dogs. How could we examine this question using the data given?
In exercise
Researchers conducted a study of the effects of three drugs on the fat content of the shoulder muscles in labrador retrievers. They divided 80 dogs at random into four treatment groups. The dogs in group A were the untreated controls, while groups B, C, and D received one of three new heartworm medications in their diets. Five dogs randomly selected from each of the four groups received treatment for periods varying from 4 months to 2 years. The percentage of fat content of the shoulder muscles was determined and is given here.