7.2: HYPOTHESIS TESTING
EXERCISES
For each of the following exercises carry out hypothesis testing procedure for the given significance level. For each exercise, appropriate, explain why you chose a one-sided test or two-sided test. Discuss how you think researcher and/or clinicians might use the results of your hypothesis test. What clinical and/or research decision and/ or actions do you think would be appropriate in light of the results test?
7.2.1: The researcher conducted a study to examine prospectively collected data on gentamicin in pharmacokinetic in three populations over 18 years of age: patients with acute leukemia, patients with other nonleukemic malignancies, and patients with no underlying malignancy or pathophysiology other than renal impairment known to alter gentamicin pharmacokinetics. Among other statistics reported by the investigators were a mean initial calculated creatinine clearance value of 59.1 with a standard deviation of 25.6 in a sample of 211 patients with malignancies other than leukemia. We wish to know if we may conclude that the mean for a population of similar subjects is less than 60. Let ? = 0.10.
ANSWER: Do not reject H0 , since -0.51>-1.28 . p=0.3085
7.2.5 : In a sample of 49 adolescents who served as the subjects in an immunologic study, one variable of interest was the diameter of skin test reaction to an antigen. The sample mean and standard deviation were 21 and 11 mm erythema, respectively. Can it be concluded from these data that the population mean is less than 30? Let ?=0.05.
ANSWER: Yes, z=-5.73. p<0.0001
7.2.11: A random sample of 16 emergency reports was selected from the files of an ambulance service. The mean time reqiured to reach their destinations was 13 minutes. Assume that the population of times is normally distributed with a variance of 9. Can we conclude at the 0.05 level of significance that the population mean is greater than 10 minutes?
ANSWER: Z=4, P<0.0001