Population A and Population B both have a mean height of 70.0 inches with an SD of 6.0. A random sample of 30 people is picked from population A, and random sample of 50 people is selected from Population B. Which sample mean will probably yield a more accurate estimate of its population mean? Why? Suppose we obtained data on vein size after application of a nitroglycerin ointment in a sample of 60 patients. The mean vein size is found to be 7.8mm with an SD of 2.5. Using a distribution table (because information on the true SEM is not available), what are the confidence limits for a 95% confidence interval? For a 99% confidence interval? For which of the following situations is the independent groups t-test appropriate (if inappropriate, why?): a. The independent variable (IV) is type of stimulation for premature infants (auditory vs visual vs tactile); the dependent variable (DV) is cardiac responsiveness. b. The IV is parental role (mother vs father); the DV is degree of bonding with the infant. c. The IV is infant birth weight (low vs normal birth weight); the DV is number of days absent from school in first grade. d. The IV is gender (male vs female); the DV is compliance vs noncompliance with a medication regimen. e. The IV is radiation treatments (before vs after treatment); the DV is cancer patients perceived self-efficacy. For which of the following situations is the dependent groups t-test appropriate (if not appropriate, why?) a. The IV is presence or absence of conversation directed to comatose patients (same patients with and without conversation); the DV is the patients intracranial pressure. b. The IV is role (patient vs nurse); the DV is perceived functional ability of the patient 48 hours after surgery. c. The IV is time since incarceration (1 months vs 3 months vs 6 months); the DV is body weight. d. The IV is menopausal state (pre vs post); the DV is attitudes toward menopause. e. The IV is nap therapy for narcoleptics (before vs after treatment); the DV is unplanned naps the following week (had unplanned vs didnt have unplanned nap). Suppose we wanted to test the hypothesis that a control group of cancer patients (Group 1) would report higher mean pain ratings than an experimental group receiving special massage treatments (Group 2). Use the following information. Compute a t-statistice for independent groups: mean group 1 = 78.5 s = 42.1 n = 25 mean group 2 = 72.1 s = 39.7 n =25 What are the degrees of freedom and the value of ? Using ?=0.05 for a two-tailed test, is this statistic significant? Write one or two sentences that could be used to report the results obtained for the t-test in Exercise 8. For each of the following t values, indicated whether the is statistically significant for a two-tailed test, at the specified alphas: = 2.40, = 25, ? = 0.01 = 2.40, = 25, ? = 0.05 = 5.52, = 10, ? = 0.01 = 2.02, = 150, ? = 0.05 For each of the following situations, indicate whether ANOVA is appropriate; if not appropriate, the reason why not; and, if appropriate, the type of ANOVA that would be used (i.e., one-way, repeated measures, etc.) a. The IV is age group people in their 60s, 70s, and 80s; the DV is health-related hardiness as measured on a 20-item scale. b. The IVs are ethnicity (white, African American, spanic) and birth weight (<2500g, ?2500g); the DV is serum bilirubin levels. c. The IV is maternal breast feeding status (breastfeeds vs doesnt breastfeed); the DV is maternal bonding with infant, as measured on a 10-item self-report scale. d. The IV is treatment group for patients with drug-induced shivering (extremity wraps vs high room temp vs normal room temp without wraps); the DV is myocardial oxygen consumption, measured before and after treatment. e. The IV is length of gestation (preterm vs term vs postterm); the DV is epidural anesthesia during labor (yes or no) Suppose we wanted to compare the somatic complaints (as measured on a scale known as the Physical Symptom Scale or PSS) of three groups of people: non-smokers, smokers, and people who recently quit smoking. Using the following data for PSS, do a one-way ANOVA to test the hypothesis that the population means are equal: 19 26 37 23 29 32 17 22 27 20 30 41 26 23 38 What are the means for the three groups? Compute the sums of squares, degrees of freedom, and mean squares for these data. What is the value of F? Using an alpha of 0.05, is the F statistic significant? For each of the following F values, indicate whether the F is statistically significant at the specified alpha level: a. F = 2.80, df = 4, 40 ? = 0.01 b. F = 5.02, df = 3, 60, ? = 0.001 c. F = 3.45, df = 3, 27, ? = 0.05 d. F = 4.99, df = 2, 150, ? = 0.01 e. F = 2.09, df = 2, 250, ? = 0.05 What is the probability of drawing a spade from a normal, shuffled deck of 52 cards? What is the probability of drawing five spades in a row (i.e., the probability of getting a flush in five-card poker?) 16) Given a normal distribution of scores with a mean of 100 and an SD of 10, compute z scores for the following raw values: 95, 115, 80, 130.
