16. Functional foods are those containing nutritional supplements in addition to natural nutrients. Examples
include orange juice with calcium and eggs with omega-3. Kolodinsky, et al. (2008) examined attitudes
toward functional foods for college students. For American students, the results indicated that females
had a more positive attitude toward functional foods and were more likely to purchase them compared to
males. In a similar study, a researcher asked students to rate their general attitude toward functional foods
on a 7-point scale (higher score is more positive). The results are as follows:
Females Male
n = 8 n = 12
M = 4.69 M = 4.43
SS = 1.60 SS = 2.72
a. Do the data indicate a significant difference in attitude for males and females? Use a two-tailed
test with = .05.
b. Compute r2, the amount of variance accounted for by the gender difference, to measure effect size.
c. Write a sentence demonstrating how the results of the hypothesis test and the measure of effect size
would appear in a research report.
18. Numerous studies have found that males report higher self-esteem than females, especially for adolescents (Kling, Hyde, Showers, & Buswell, 1999). Typical results show a mean self-esteem score of M = 39.0 with SS = 60.2 for a sample of n =10 male adolescents and a mean of M =35.4 with SS= 69.4 for a sample of n =10 female adolescents.
a. Do the results indicate that self-esteem is significantly higher for males? Use a one-tailed test with = .01.
b. Use the data to make a 95% confidence interval estimate of the mean difference in self-esteem
between male and female adolescents.
c. Write a sentence demonstrating how the results from the hypothesis test and the confidence interval
would appear in a research report.
20. When people learn a new task, their performanceusually improves when they are tested the next day,
but only if they get at least 6 hours of sleep (Stickgold, Whidbee, Schirmer, Patel, & Hobson, 2000). The
following data demonstrate this phenomenon. The participants learned a visual discrimination task on one
day, and then were tested on the task the following day. Half of the participants were allowed to have at
least 6 hours of sleep and the other half were kept awake all night. Is there a significant difference
between the two conditions? Use a two-tailed test with =.05.
Performance Scores
6 Hours of Sleep No Sleep
n =14 n =14
M =72 M =65
SS =932 SS =706
22. Downs and Abwender (2002) evaluated soccer players and swimmers to determine whether the routine blows to the head experienced by soccer players produced long-term neurological deficits. In the study,
neurological tests were administered to mature soccer players and swimmers and the results indicated
significant differences. In a similar study, a researcher obtained the following data.
Swimmers Soccer players
10 7
8 4
7 9
9 3
13 7
7
6
12
a. Are the neurological test scores significantly lower for the soccer players than for the swimmers in the
control group? Use a one-tailed test with= .05.
b. Compute the value of r2 (percentage of variance accounted for) for these data.
1 answer
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