A veterinarian interested in studying the causes of enteroliths in horses suspects that a diet high in alfalfa may be a cause. The veterinarian decides to use the following design: identify 30 horses at high risk for enteroliths, and divide them into 10 groups of 3 horses. Some groups consist of horses in barn stalls, some groups consist of horses in outdoor paddocks, and some groups consist of horses in pastures. Within each group, one horse is randomly assigned to an alfalfa diet, one is assigned to a grass hay diet, and one horse is fed oat hay. When a horse is in a pasture, all the other horses in that pasture will also receive the diet of the study horse. Therefore, only one horse can be selected from a given pasture. After one year, the horses are given radiographs to determine if enteroliths are present in the gut. The response is:
A)the diet a horse is given.
B)the amount of feed a horse is given.
C)the number of enteroliths.
D)the presence or absence of enteroliths.

Question

Quizplus · Accepted Answer

The response in this study is the presence or absence of enteroliths, as the goal is to determine if a high alfalfa diet is a cause of enteroliths in horses. The other variables (diet and amount of feed) are independent variables being manipulated in the study. The number of enteroliths is not the best choice as it is not a binary outcome and may vary in severity.

A Veterinarian Interested in Studying the Causes of Enteroliths in Horses