PSYC 355
SPSS HOMEWORK 1 INSTRUCTIONS:
SINGLE-SAMPLE T-TESTS AND PAIRED-SAMPLE T-TESTS
When submitting this file, be sure the filename includes your full name, course, and section.
Example: HW1_JohnDoe_355B03
Part One:
Please note that for all problems in this course, the standard cut-off for a test of
significance will be p < .05 unless otherwise noted in the problem.
1. Single-Sample t test: based on Green and Salkind Lesson 22 Exercise 1–4, but follow the
instructions below instead.
Open the Lesson 22 Exercise File found in Blackboard Course content (under Course Guides and
Assignment Instructions>Assignment Instructions>SPSS Homework 1>SPSS Homework 1
Files>Mod1_Lesson 22 Exercise File 1). Always use the Blackboard files instead of the files on
the Green and Salkind website as some files have been modified for the purposes of this course.
1. A total score variable is included in the data file in Blackboard (“tot_score”), so you do
not have to compute it. Use this variable as your dependent variable.
2. The test value for the single-sample t-test is 2 (1/4 of 8, or the score which a student
would achieve by chance). Use 2 as the test value when running the analysis for this
exercise.
3. Conduct a single-sample t-test on the total score variable. Paste the output into your
Microsoft Word document and type in the answers to the following questions underneath
the output: (2 pts for output)
One-Sample Statistics
N Mean Std. Deviation Std. Error Mean
Tot_Score 6 6.0000 1.41421 .57735
One-Sample Test
Test Value = 2
t df Sig. (2-tailed) Mean Difference
95% Confidence Interval of the
Difference
Lower Upper
Tot_Score 6.928 5 .001 4.00000 2.5159 5.4841
a. Mean algebra score (2 pts) 6.0
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PSYC 355
b. t test value (the result of the t test, not the “test value” which is already given) (2
pts) 6.93
c. p value (significance) of the test (2 pts) p<.01
4. Write a current APA-style Results section based on your analysis. All homework “Results
sections” must follow the example given in the SPSS tutorials and the Course Content
document “Writing Results of Statistical Tests in Current APA Format” (note: you do not
have to refer to a figure). Remember to include a decision about the null hypothesis. (2
pts)
A single-sample t test was conducted to determine whether a new teaching method, the
Involvement Technique, was effective in teaching algebra to first graders. The
established population mean for total scores for the algebra test is 6. Results indicated a
significant difference, t(5) = 6.93, p<.01. First graders who participated in the new
teaching method, scored higher on the algebra test than the general population. Thus, the
null hypothesis that first graders who participated in the new teaching method, the
Involvement Technique, were more effective in teaching algebra is rejected.
5. Create a histogram that demonstrates the distribution of scores. Be sure to correctly label
the X and Y axes and give your graph a title. (2 pts)
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PSYC 355
2. Green and Salkind Lesson 23 Exercises 6–8: (Lesson 23 Exercise File 1)
The following helpful tips are numbered to correspond with the exercise number to which they
refer within the Green and Salkind text:
6. Instead of identifying these values on your output, as the text states, please write them
into your Microsoft Word file as written answers for #6 a, b, c, and d. (output = 2 pts; a–d
= 2 pts. each)
Paired Samples Statistics
Mean N Std. Deviation
Std. Error
Mean
Pair 1 Husband's infertility
anxiety score 57.46 24 7.337 1.498
Wife's infertility anxiety
score 62.54 24 12.441 2.540
Paired Samples Correlations
N Correlation Sig.
Pair 1 Husband's infertility anxiety
score & Wife's infertility anxiety
score
24 .822 .000
Paired Samples Test
Paired Differences
t df
Sig. (2-
tailed)Mean
Std.
Deviation
Std.
Error
Mean
95% Confidence
Interval of the
Difference
Lower Upper
Pair
1
Husband's infertility anxiety
score - Wife's infertility
anxiety score
-
5.083 7.649 1.561 -8.313 -1.853 -
3.256 23 .003
a) 57.5
b) 62.5
c) -3.256
d) .003
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PSYC 355
7. Write a current APA-style Results section based on your analyses. All homework “Results
sections” must follow the example given in the SPSS tutorials and the Course Content
document “Writing Results of Statistical Tests in Current APA Format” (note: you do not
have to refer to a figure). Remember to include a decision about the null hypothesis. (3
pts)
A paired-samples t test was conducted to determine whether husbands and wives who are
having infertility problems feel equally anxious. The results show that mean cocern
ratings were significantly different, t(23) = -3.256, p = .003. Concerns about husbands
(M = 57.5, sd = 7.34) were rated significantly lower than concerns about wives (M =
62.5, sd = 12.4). The null hypothesis that husbands and wives experiencing infertility
feel equally anxious, is rejected.
8. You will create the boxplot here instead of in the Results section. (2 pts)
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PSYC 355
Part Two:
1. A counseling psychologist administers an interview assessment that screens for possible
internet addiction to his adolescent clients who live in a rural area. He assumes that children in
this area may exhibit higher scores than children in the general population, who normally score a
20 on a scale of 1-100. The table below shows the scores the counselor has collected. Using the
table, enter the data into a new SPSS file and conduct a single sample t-test to evaluate
whether or not these adolescents scored higher than the general population.
The steps will be the same as the ones you have been practicing in Part One of the assignment—
the only difference is that you are now responsible for creating the data file as well. Remember
to name and define your variables under the “Variable View,” then return to the “Data View” to
enter the data.
Internet Addiction
Interview Scores
22
57
63
17
10
18
9
51
46
9
23
3
18
55
12
27
a) Paste SPSS output (2 pts)
One-Sample Statistics
N Mean Std. Deviation Std. Error Mean
InternetAddIntScores 16 27.5000 19.92319 4.98080
One-Sample Test
Test Value = 20
t df Sig. (2-tailed) Mean Difference
95% Confidence Interval of the
Difference
Lower Upper
InternetAddIntScores 1.506 15 .153 7.50000 -3.1163 18.1163
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PSYC 355
b) Write a current APA-style Results section based on your analyses. All homework “Results
sections” must follow the example given in the SPSS tutorials and the Course Content
document “Writing Results of Statistical Tests in Current APA Format” (note: you do not
have to refer to a figure). Remember to include a decision about the null hypothesis. (3
pts)
A single- sample t test was conducted to determine whether children who live in rural
areas exhibit higher scores for internet addiction than the general population. The
established population mean for children in rural areas is 27.5. Results indication a
significant difference between the means, t(15) = 1.51, p = .153. Children who live in
rural areas scored lower than the general population of children addicted to internet (M =
27.5, SD = 19.9). Thus, the null hypothesis that children who live in rural areas score
higher than the general population, is rejected.
c) Create a histogram that demonstrates the distribution of scores. Be sure to correctly label
the X and Y axes. (2 pts)
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PSYC 355
2. A clinical psychologist is studying the differences in the number of Facebook® friends
between identical twins raised apart. She believes that twins raised in different environments will
have differences in the number of friends, which would help point to the influence of
environmental factors over inherited factors on social outcomes. She divides the twins into two
groups (“Twin 1” and “Twin 2”), collects the data, and creates the table below. Using this table,
enter the data into a new SPSS data file and run a paired-samples t test to test the claim
that the identical twins raised apart will have a significantly different number of
Facebook® friends.
The steps will be the same as the ones you have been practicing in Part One of the assignment—
the only difference is that you are now responsible for creating the data file as well. Remember
to name and define your variables under the “Variable View,” then return to the “Data View” to
enter the data.
a) Paste SPSS output (2 pts)
Paired Samples Statistics
Mean N Std. Deviation Std. Error Mean
Pair 1 TWIN1 113.1250 16 78.48046 19.62012
TWIN2 101.3750 16 60.91948 15.22987
Paired Samples Correlations
N Correlation Sig.
Pair 1 TWIN1 & TWIN2 16 .705 .002
Paired Samples Test
Paired Differences
t df
Sig. (2-
tailed)Mean
Std.
Deviation
Std. Error
Mean
95% Confidence Interval of the
Difference
Lower Upper
Pair
1
TWIN1 -
TWIN2 11.75000 55.97916 13.99479 -18.07919 41.57919 .840 15 .414
b) Write a current APA-style Results section based on your analysis. All homework “Results
sections” must follow the example given in the SPSS tutorials and the Course Content
document “Writing Results of Statistical Tests in Current APA Format” (note: you do not
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Twin 1 Twin 2
254
64
91
78
89
178
47
205
21
90
136
19
40
212
231
55
196
61
119
43
79
180
61
116
101
87
126
51
56
247
70
29
PSYC 355
have to refer to a figure). Remember to include a decision about the null hypothesis. (2
pts)
A paired-samples t test was conducted to determine whether twins who grew up in
different environments have a differen number of Facebook friends. The results show
that mean concern ratings on the two varieables were significantly different, t(15) = .840,
p = .414. Concerns about TWIN1 (M = 113.13, SD = 78.5). were rated as significantly
higher than concerns about TWIN2 ( M = 101.48, SD = 60.9). The null hypothesis that
the two twins have different amounts of Facebook friends because of being in different
environments, is rejected.
c) Create a boxplot comparing the twins’ scores. Be sure to correctly label the X and Y axes.
(2 pts)
Submit this assignment by 11:59 p.m. (ET) on Monday of Module/Week 1.
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