Witte & Witte, 9e
Chapter 21
Page 1 of 9 Pages
Chapter 21: Postscript: Which Test?
Exercise 1
Perilou Goddard (2003) designed a Writing in Psychology course to help college students
learn important skills needed for the preparation of formal psychological research reports.
Students were administered precourse and postcourse tests on their knowledge of the
writing style recommended by the American Psychological Association. Goddard carried
out a statistical analysis on the precourse and postcourse means.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
2
h. Onetest
2
i. Twotest
A paragraph from Goddard’s results section is shown below. Use the information
presented in this paragraph to answer questions 2 to 7.
The maximum possible number of correct answers on the APA style
tests was 40. The precourse mean score was 20.74 (SD = 3.80); the
postcourse mean score improved to 23.85 (SD = 4.23). Again, a twotailed paired-sample t test revealed a significant difference t(26) =
-3.68, p = .001. (p. 28)
2. The standard deviation of the precourse test scores was equal to ___.
3. The standard deviation of the postcourse test scores was equal to ___.
4. The obtained precourse-postcourse difference between the means was equal to
___.
5. Degrees of freedom for the analysis were equal to ___.
6. How many students provided test scores for the analysis?
7. With a significance level of .05, critical t is equal to ___. (Use the appropriate
table in your textbook.)
Answers:
1.
2.
3.
4.
5.
c. t test for two related samples
3.80
4.23
20.74 – 23.85 = –3.11
26
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Chapter 21
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6. 27
7. ±2.056
Exercise 2
Barbara Hofer and Shirley Yu (2003) assessed the impact of a Learning to Learn course
on college students’ motivation and cognitive processing. Hofer and Yu wanted to find
out if motivation was related to cognitive processing behavior. Students completed a
questionnaire that included items related to cognitive processing behaviors as well as
academic motivation. Six aspects of motivation were correlated with seven aspects of
cognitive processing behaviors.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
2
h. Onetest
2
i. Twotest
A paragraph from the authors’ results section is shown below. Use the information
presented in this paragraph to answer questions 2 to 7.
The second research question concerned the relations among the
motivational and cognitive variables… Most notably at Time 1,
intrinsic goal orientation was positively correlated with deep
processing, r(75) = .26, p < .05; planning, r(75) = .34, p < .01;
monitoring, r (75) = .37, p < .01; and metacognition, r(75) = .42, p <
.05. (p. 31)
2. Pearson’s correlation (r) between intrinsic goal orientation and planning was
equal to ___.
3. Pearson’s correlation (r) between intrinsic goal orientation and monitoring was
equal to ___.
4. The strongest correlation of the four r’s presented in the paragraph was ___. This
was the correlation between ___ and ___.
5. Degrees of freedom for each statistical test were equal to ___.
6. How many students provided test scores for the analysis?
7. With a significance level of .05 for a one-tailed test, critical t is equal to ___.
(Use the appropriate table in your textbook.)
Answers:
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Chapter 21
1.
2.
3.
4.
5.
6.
7.
Page 3 of 9 Pages
d. t test for a correlation coefficient
r = .34
.37
.42; intrinsic goal orientation and metacognition
df = 75
77
1.671
Exercise 3
Undergraduate psychology majors frequently obtain a variety of research experiences.
Bowman and Waite (2003) conducted an investigation to find out if the type of research
participation had an effect on student satisfaction. College students engaged in one type
of research experience (volunteer in a research study, mass testing, or writing a research
paper) and then completed a research satisfaction questionnaire. Bowman and Waite
recorded the satisfaction scores and carried out an analysis on the three satisfaction
means.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
h. One-variable 2 test
2
i. Twotest
A paragraph from their results section is shown below. Use the information presented in
this paragraph to answer questions 2 to 7. Note: LSD refers to Fisher’s least significant
difference test. Fisher’s LSD test is a multiple comparison test procedure that is similar
to the Tukey’s HSD test that is discussed in your textbook. (In the direct quote below,
this multiple comparison test is referred to as a “post hoc” test.)
We found significant differences in student satisfaction by type of
research (volunteering in a research study, mass testing, or paper)
using a one-way ANOVA, F(2, 517) = 8.14, p < .01. Post hoc LSD tests
revealed that students who participated as a volunteer in a research
study were more satisfied than both those who participated in mass
testing and those engaged in the paper-writing activity. (p. 104).
2.
3.
4.
5.
Degrees of freedom between groups was equal to ___.
Degrees of freedom within groups was equal to ___.
Total degrees of freedom is equal to ___.
How many students provided data for the analysis?
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Chapter 21
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6. The obtained F value was equal to ___.
7. With a significance level of .01, critical F is equal to ___. (Use the appropriate
table in your textbook.)
Answers:
1.
2.
3.
4.
5.
6.
7.
e. One-factor F-test
Between groups df = 2
Within groups df = 517
Total df = 519
N = 520
Obtained F = 8.14
Critical F = 4.66
Exercise 4
A classic finding in psychological research is that people cannot tell when others are
lying to them, yet they are very confident of their lie detection abilities. Kathryn Morris
(2003) created an exercise for her social psychology students that was designed to
enhance their understanding of the relation between confidence and accuracy in lie
detection. To evaluate the effectiveness of the exercise, Morris recruited 32 students.
She randomly assigned 17 of these students to participate in the exercise, and the
remaining 15 students did not participate in the exercise. All 32 students completed a test
on confidence and accuracy in lie detection. The tests were graded as either correct or
incorrect. Morris’ results could be displayed in a 2 × 2 table where test result (correct or
not correct) is cross tabulated by whether or not the student participated in the exercise.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
2
h. Onetest
2
i. Twotest
A paragraph from Morris’ results section is shown below. Use the information presented
in this paragraph to answer questions 2 to 7.
After grading answers on a correct-incorrect dichotomy, a chi-square
analysis revealed that significantly more students who participated in
the exercise (71%) correctly understood the (non)relation between
confidence and accuracy in lie detection ability than did students who
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Chapter 21
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had not participated in the exercise (13%),
.01. (p. 113)
2(1,
N = 32) = 10.61, p <
2. The degrees of freedom for the analysis were equal to ___.
2
3.
was equal to ___.
2
4.
is equal to ___. (Refer to the
appropriate table in your textbook.)
5. What null hypothesis was Morris testing?
6. What was the alternative hypothesis?
7. Based on her results, what statistical decision would Morris have made? Reject or
retain the null hypothesis?
Answers:
1.
2.
3.
4.
5.
6.
7.
2
i. Twodf = 1
test
2
= 10.61
= 6.64
H0: Participation in the exercise and test grade are independent.
H1: H0 is false.
Reject the null hypothesis.
2
Exercise 5
Kowalski and Taylor (2009) observed that students in an introductory psychology course
often enter the course with misconceptions and complete the course with the
misconceptions intact. One example of a misconception is that “most people use only
10% of their brain power” (p. 153). Kowalski and Taylor designed a study to find out
whether refutational lectures and readings would be effective in dispelling
misconceptions of introductory psychology students. The investigators identified 45
misconceptions and embedded them in a Psychological Information Questionnaire that
was administered as a pretest during the first class. Nine misconceptions were then
assigned to one of five different combinations of coverage in a within-subjects design
where all students received all five combinations. The five combinations were: (a)
refutational lecture and refutational reading, (b) refutational lecture and no reading, (c)
standard lecture and standard reading, (d) no lecture and refutational reading, and (e) no
lecture and no reading. At the end of the course, the students again completed the
Psychological Information Questionnaire. A normalized gain score was calculated for
each student and the mean gain score was computed for each combination of coverage.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
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Chapter 21
f.
g.
h.
i.
Page 6 of 9 Pages
Two-factor F-test
Repeated-measures F test
2
Onetest
2
Twotest
A paragraph from Kowalski and Taylor’s results section is shown below. Use the
information presented in this paragraph to answer questions 2 to 5.
The initial analysis involved a one-way repeated measures ANOVA assessing
the effect of the five different coverage methods on <g>. This overall
ANOVA was significant, F(4,61) = 110.42, p < .001, 2 = .88. (p. 156)
2. Numerator degrees of freedom were equal to ___.
3. Denominator degrees of freedom were equal to ___.
4. With a significance level of .05, critical F is equal to ___. (Use the appropriate
table in your textbook.)
5. The proportion of explained variance was equal to ___.
Answers:
1.
2.
3.
4.
5.
g. Repeated-measures F test
4
61
2.52
.88
Exercise 6
Johnson and Kiviniemi (2009) designed a study to investigate the effect of online chapter
quizzes on exam performance in a social psychology course. The online quizzes were
completed by all students prior to taking an exam. Each exam question was categorized
as either covered by an online quiz or not covered by an online quiz. The researchers
compared the proportion of correct responses to exam questions covered by a quiz to the
proportion of correct responses to exam questions not covered by a quiz.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
h. One-variable 2 test
2
i. Twotest
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Chapter 21
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One sentence from the results section is shown below. Use the information presented in
this sentence to answer questions 2-7.
Overall, performance was better for those questions that had been covered by a
reading quiz (M = 70%, SD = 9%) versus those not covered by a quiz (M = 65%, SD
= 14%); paired t(157) = 5.03, p < .001, d = 45. (p. 35)
2.
3.
4.
5.
6.
7.
The mean percent correct on questions covered by a quiz was equal to ___.
The mean percent correct on questions not covered by a quiz was equal to ___.
The obtained difference was equal to ___.
Degrees of freedom for the analysis were equal to ___.
How many students provided test scores for the analysis?
With a significance level of .05, critical t for a one-tailed test is approximately
equal to ___. (Use the appropriate table in your textbook.)
Answers:
1.
2.
3.
4.
5.
6.
7.
c. t test for two related samples
70%
65%
5%
157
158
1.65
Exercise 7
Dietz-Uhler and Lanter (2009) devised a four-questions technique to help students
understand material presented in an introductory psychology course. At the end of the
course, the students completed a questionnaire indicating how successful they thought the
technique was with respect to helping them think more deeply about the content. A
seven-point response scale was used where 1 indicated not very successful and 7
indicated very successful. To analyze the students’ responses, the mean response was
calculated and compared to 4.0, the midpoint of the response scale.
1. Which statistical test seems most appropriate for the statistical analyses?
a. t test for one sample
b. t test for two independent samples
c. t test for two related samples
d. t test for a correlation coefficient
e. One-factor F-test
f. Two-factor F-test
g. Repeated-measures F test
2
h. One-v
test
2
i. Twotest
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Chapter 21
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Part of the results section is shown below. Use this information to answer questions 2-7.
Therefore, we collapsed across order and topic and conducted one-sample t
tests using the midpoint (4.0) of the scale as the test statistic. Results showed
that participants perceived the activity to be successful in meeting its goals
(M = 4.65, SD = 1.06), t(97) = 6.03, p < .01 . . . (p. 40)
2.
3.
4.
5.
6.
7.
Observed t was equal to ___.
The mean response was equal to ___.
The standard deviation of the responses was equal to ___.
Degrees of freedom for the analysis were equal to ___.
How many students provided responses for the analysis?
With a significance level of .05, critical t for a nondirectional test is
approximately equal to ___. (Use the appropriate table in your textbook.)
Answers:
1.
2.
3.
4.
5.
6.
7.
a. t test for one sample
6.03
4.65
1.06
97
98
2.00
References
Bowman, L. L., & Waite, B. M. (2003). Volunteering in research: Student satisfaction
and educational benefits. Teaching of Psychology, 30, 102-106.
Dietz-Uhler, B., & Lanter, J. R. (2009). Using the four-questions technique to enhance
learning. Teaching of Psycholoogy, 36, 38-41.
Goddard, P. (2003). Implementing and evaluating a writing course for psychology
majors. Teaching of Psychology, 30, 25-29.
Hofer, B. K., & Yu, S. L. (2003). Teaching self-regulated learning through a “learning
to learn” course. Teaching of Psychology, 30, 30-33.
Johnson, B. C., & Kiviniemi M. T. (2009). The effect of online chapter quizzes on exam
performance in an undergraduate social psychology course. Teaching of
Psychology, 36, 33-37.
Kowalski, P., & Taylor, A. K. (2009). The effect of refuting misconceptions in the
introductory psychology class. Teaching of Psychology, 36, 153-159.
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Chapter 21
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Morris, K. A. (2003). Teaching students about classic findings on the detection of
deception. Teaching of Psychology, 30, 111-113.
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