Chapter 16, Problem 20CE

Instructions: In all exercises, you may use a computer package (e.g., MegaStat, Minitab) or show Excel calculations in a worksheet, depending on your instructor’s wishes. Include relevant output or screen shots to support your answers. If you do the calculations yourself, show your work. State the hypotheses and give the test statistic and its two-tailed p-value. Make the decision. If the decision is close, say so. Are there issues of sample size? Is non-normality a concern?

16.20 A cognitive retraining clinic assists outpatient victims of head injury, anoxia, or other conditions that result in cognitive impairment. Each incoming patient is evaluated to establish an appropriate treatment program and estimated length of stay (ELOS is always a multiple of 4 weeks because treatment sessions are scheduled on a monthly basis). To see if there is any difference in ELOS between the two clinics, a sample is taken, consisting of all patients evaluated at each clinic during October, with the results shown. Research question: At α = .10, do the medians differ?