Chapter 14, Problem 53E

Exercises 53 through 56 refer to a study conducted between 2008 and 2010 on the effectiveness of saw palmetto fruit extracts at treating lower urinary tract symptoms in men with prostate enlargement. (Saw palmetto is a widely used over-the-counter supplement for treating urinary tract symptoms.) In the study, 369 men aged 45 years or older were randomly divided into a group taking a daily placebo and a group taking saw palmetto. Participants were nonpaid volunteers recruited at 11 North American sites. All had moderately impaired urinary flow. Because the saw palmetto extract has a mild odor, the doses were administered using gelcaps to eliminate the odor. In an analysis of the 306 men who completed the 72- week trial, both groups had similar small improvements in mean symptom scores, but saw palmetto conferred no benefit over placebo on symptom scores or on any secondary outcomes. [Source: Journal of the American Medical Association, 306(12), 2011, 1344—1351.]

a. Describe as specifically as you can the target population for the study.

b. Compare and contrast the sampling frame and target population for the study.