Statistics for the Behavioral Sciences by Frederick J. Gravetter, Larry B. Wallnau ISBN 10: 1305504917 ISBN 13: 9781305504912

PROBLEMS 331
c. Write a sentence demonstrating how the results of
the hypothesis test and the measure of effect size
would appear in a research report.
11. Recent research has shown that creative people are
more likely to cheat than their less creative counterparts
(Gino and Ariely, 2012). Participants in the
study first completed creativity assessment questionnaires
and then returned to the lab several days later
for a series of tasks. One task was a multiple-choice
general knowledge test for which the participants
circled their answers on the test sheet. Afterward,
they were asked to transfer their answers to a bubble
sheets for computer scoring. However, the experimenter
admitted that the wrong bubble sheet had
been copied so that the correct answers were
still faintly visible. Thus, the participants had an
opportunity to cheat and inflate their test scores.
Higher scores were valuable because participants
were paid based on the number of correct answers.
However, the researchers had secretly coded the
original tests and the bubble sheets so that they could
measure the degree of cheating for each participant.
Assuming that the participants were divided into
two groups based on their creativity scores, the
following data are similar to the cheating scores
obtained in the study.
High Creativity
Participants
Low Creativity
Participants
n = 27 n = 27
M = 7.41 M = 4.78
SS = 749.5 SS = 830
a. Use a one-tailed test with α = .05 to determine
whether these data are sufficient to conclude that
high creativity people are more likely to cheat than
people with lower levels of creativity.
b. Compute Cohen’s d to measure the size of the
effect.
c. Write a sentence demonstrating how the results
from the hypothesis test and the measure of effect
size would appear in a research report.
12. Recent research has demonstrated that music-based
physical training for elderly people can improve
balance, walking efficiency, and reduce the risk of
falls (Trombetti et al., 2011). As part of the training,
participants walked in time to music and responded
to changes in the music’s rhythm during a 1-hour per
week exercise program. After 6 months, participants
in the training group increased their walking speed
and their stride length compared to individuals in the
control group. The following data are similar to the
results obtained in the study.
Exercise Group
Stride Length
Control Group
Stride Length
24 25 22 24 26 23 20 23
26 17 21 22 20 16 21 17
22 19 24 23 18 23 16 20
23 28 25 23 25 19 17 16
Do the results indicate a significant difference in the
stride length for the two groups? Use a two-tailed test
with α = .05.
13. McAllister et al. (2012) compared varsity football and
hockey players with varsity athletes from noncontact
sports to determine whether exposure to head impacts
during one season have an effect on cognitive performance.
In the study, tests of new learning performance
were significantly poorer for the contact sport athletes
compared to the noncontact sport athletes. The following
table presents data similar to the results obtained
in the study.
Noncontact Athletes
Contact Athletes
10 7
8 4
7 9
9 3
13 7
7 6
6 10
12 2
a. Are the test scores significantly lower for the contact
sport athletes than for the noncontact athletes?
Use a one-tailed test with α = .05.
b. Compute the value of r 2 (percentage of variance
accounted for) for these data.
14. In the Chapter Preview we presented a study showing
that handling money reduces the perception pain
(Zhou, Vohs, & Baumeister, 2009). In the experiment,
a group of college students was told that they were
participating in a manual dexterity study. Half of the
students were given a stack of money to count and the
other half got a stack of blank pieces of paper. After
the counting task, the participants were asked to dip
their hands into bowls of very hot water (122°F) and
rate how uncomfortable it was. The following data
show ratings of pain similar to the results obtained
in the study.