1. For each of the following t values, indicate whether the t is statistically significant for a two-tailed test, at the specified alphas:
a. t = 2.90, df = 25, α = 0.01
b. t = 2.00, dr = 25, α = 0.05
c. t = 5.52, df = 10, α = 0.01
d. t = 2.02, df = 150, α = 0.05
1. 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 IVs are ethnicity (Asian, White, African American, Hispanic) and gender (male vs female); the DV is serum cholesterol levels.
b. The IV is smoking status - smokers vs non-smokers; the DV is health-related hardiness as measured on a 20-item scale.
c. The IV is maternal breast feeding status (breastfeeds daily vs breastfeeds at least 1-3 times/week vs doesn't breastfeed); the DV is maternal bonding with infant, as measured on a 20-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) same patient used for each treatment; 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 delivery type (vaginal vs Caesarean).
2. 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:
Nonsmokers Smokers Quitters
19 31 30
28 29 22
17 22 23
20 24 22
25 19 17
Using StatCrunch, determine the means for the three groups and 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? Why? Copy and Paste your work from StatCrunch into your Word document submission.
3. A new motorcycle is being developed to meet new gas mileage standards recently passed by the federal government. An engineer tested three model designs by randomly assigning the motorcycles in a blind study (the riders recorded the mileage but did not know the design of the motorcycle, only its code). The data in miles per gallon (MPG) for the three designs is listed below:
|
X-1
|
B-1
|
Z-1
|
|
45
|
55
|
54
|
|
62
|
55
|
52
|
|
50
|
54
|
41
|
|
65
|
44
|
35
|
|
62
|
52
|
38
|
|
50
|
69
|
41
|
|
50
|
58
|
51
|
|
58
|
45
|
44
|
Using StatCrunch, determine the means for the three groups and compute the sums of squares, degrees of freedom, and mean squares for these data. What are the hypotheses to be tested here? What is the value of F? Using an alpha of 0.05, is the F statistic significant? Why? Copy and Paste your work from StatCrunch into your Word document submission for full credit.
4. For each of the following F values, indicate whether the F is statistically significant at the specified alpha level:
a. F = 4.80, df = 4, 40 α = 0.01
b. F = 5.02, df = 3, 60, α = 0.001
c. F = 3.45, df = 3, 27, α = 0.05
d. F = 4.99, df = 2, 150, α = 0.01
e. F = 2.09, df = 2, 250, α = 0.05