Animal-assisted therapy for heart patients. Refer to the American Heart Association Conference (Nov. 2005) study to gauge whether animal-assisted therapy can improve the physiological responses of heart failure patients, presented in Exercise 2.112

(p. 106). Recall that a sample of n = 26 heart patients was visited by a human volunteer accompanied by a trained dog; the anxiety level of each patient was measured (in points) both before and after the visits.

The drop (before minus after) in anxiety level for patients is summarized as follows: xd = 10.5, sd = 7.6. Does animal-

assisted therapy significantly reduce the mean anxiety level of heart failure patients? Support your answer with a 95% confidence interval.