PSY520 Topic 6 Exercises latest
PSY520 Topic 6 Exercises latest
Complete the following exercises located at the end of each chapter and put them into a word document.
Show all revelant work; use the equation editor in Microsoft word when necessary
REVIEW QUESTIONS 379
(16.9) Given the aggression scores below for Outcome A of the sleep deprivation experiment, verify that, as suggested earlier, these mean differences shouldn’t be taken seriously by testing the null hypothesis at the .05 level of significance. Use the computation formulas for the various sums of squares and summarize results with an ANOVA table.
HOURS OF SLEEP DEPRIVATION
ZERO TWENTY-FOUR FORTY-EIGHT
3 4 2
5 8 4
7 6 6
Group mean: 5 6 4 Grand mean = 5
(*16.10) Another psychologist conducts a sleep deprivation experiment. For reasons beyond his control, unequal numbers of subjects occupy the different groups. (Therefore, when calculating in SS between and SS within, you must adjust the denominator term, n, to reflect the unequal numbers of subjects in the group totals.)
(a) Summarize the results with an ANOVA table. You need not do a step-by step hypothesis test procedure.
ΣT 2
n
HOURS OF SLEEP DEPRIVATION
ZERO TWENTY-FOUR FORTY-EIGHT
1 4 7
3 7 12
6 5 10
2 9
1
(b) If appropriate, estimate the effect size with h2.
(c) If appropriate, use Tukey’s HSD test (with –n 5 4 for the sample size, n) t–o identify pairs of means that contribute to the significant F, given that X0 5 2.60, –X24 5 5.33, and –X48 5 9.50.
(d) If appropriate, estimate effect sizes with Cohen’s d.
(e) Indicate how all of the above results would be reported in the literature, given sample standard deviations of s 0 5 2.07, s 24 5 1.53, and s 48 5 2.08.
Answers on page 523 .
(*16.12) For some experiment, imagine four possible outcomes, as described in the following ANOVA table.
REVIEW QUESTIONS 381
(a) How many groups are in Outcome D?
(b) Assuming groups of equal size, what’s the size of each group in Outcome
C?
(c) Which outcome(s) would cause the null hypothesis to be rejected at the
.05 level of significance?
(d) Which outcome provides the least information about a possible treatment
effect?
(e) Which outcome would be the least likely to stimulate additional research?
(f) Specify the approximate p -values for each of these outcomes.
Answers on page 524.
(16.14) The F test describes the ratio of two sources of variability: that for subjects
treated differently and that for subjects treated similarly. Is there any sense
in which the t test for two independent groups can be viewed likewise?
Ans: 16.10
ANSWERS TO SELECTED QUESTIONS 523
16.10 (a)
SOURCE SS df MS F
Between 106.05 2 53.03 13.70*
Within 34.87 9 3.87
Total 140.92 11
* Significant at the .05 level.
ANSWERS TO SELECTED QUESTIONS 523
(b) η2 106 05
140 92
= . = 75
.
. , a large effect, according to the guidelines.
(c) HSD(k 5 3, df within 5 9) 5 (3.95) 3 87
4
. 5 (3.95)(0.98) 5 3.87
ALL POSSIBLE ABSOLUTE DIFFERENCES
BETWEEN PAIRS OF MEANS
–
X0 5 2.60
–
X24 5 5.33
–
X48 5 9.50
X
–
0 5 2.60 — 2.73 6.90*
–
X24 5 5.33 — 4.17*
–X48 5 9.50 —
* Significant at the .05 level.
(d) d(
–
X48,
–
X0) 5 6 90
3 87
.
.
5 3.50
d(
–
X48,
–
X24) 5 4 17
3 87
.
.
5 2.12
(e) Aggression scores for subjects deprived of sleep for 0 hours (
–
X 5 2.60, s 5
2.07) for 24 hours (
–
X 5 5.33, s 5 1.53), and for 48 hours (
–
X 5 9.50, s 5 2.08)
differ significantly [ F (2,9) 5 13.70, MSE 5 3.87, p , .05, η 2 5 .75]. According
to Tukey’s HSD test, the mean differences between the 24- and 48-hour groups
(4.17) and between the 0- and 48-hour groups (6.90) are significant ( HSD 5
3.87, p , .05, d 5 2.12, 3.50).
(b) Students who attend either two or three workshop sessions initiate, on average, more eye contacts than those who attend zero sessions. Furthermore, those who attend three sessions initiate, on average, more eye contacts than those who attend one session. All three significant differences had large effect sizes, with d values ranging from 1.55 to 2.69. PSY520 Topic 6 Exercises latest
16.8 (a) η2 54 00
76 00
= . = 71
.
.
(b) MSerror = 3.67 = 1.915 (which also is listed as the pooled standard
deviation).
(c) Only the limits for CI between 0 and 48 hours have the same signs (both negative)
in agreement with the one signifi cant difference between 0 and 48 hours
described in Table 16.8.
16.10 (a)
SOURCE SS df MS F
Between 106.05 2 53.03 13.70*
Within 34.87 9 3.87
Total 140.92 11
* Signifi cant at the .05 level.
Copyright © 2015 John Wiley & Sons, Inc.
524 ANSWERS TO SELECTED QUESTIONS
16.12 (a) 4
(b) 21
(c) A and B
(d) D. Because of the small number of subjects, only a larger treatment effect would
have been detected.
(e) C. Because of the relatively large number of subjects, even a fairly small treatment
effect would have been detected.
(f) For A, p , .05 For C, p . .05
For B, p , .01 For D, p . .05
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