Chapter 18, Problem 16P

1. Stressful or traumatic experiences can often worsen other health-related problems such as asthma or rheumatoid arthritis. However if patients are instructed to write about their stressful experiences, it can often lead to improvement in health (Smyth, Stone, Hurewitz, & Kaell, 1999). In a typical study, patients with asthma or arthritis are asked to write about the “most stressful event of your life.” In a sample of n = 112 patients, suppose that 64 showed improvement in their symptoms, 12 showed no change, and 36 showed worsening symptoms.
2. If the 12 patients showing no change are discarded are these results sufficient to conclude that the writing had a significant, effect? Use a two-tailed test with a = .05.
3. If the 12 patients who showed no change are split between the two groups, are the result sufficient to demonstrate a significant change? Use a two-tailed test with a = .05.