Multiple Choice items:
1. Which of the following are assumptions underlying the use of parametric tests (based on the normal distribution)?
a. the data should be normally distributed
b. the samples being tested should have approximately equal variances
c. your data should be at least interval level
d. all of the above
2. If a distribution is multimodal, what does this mean?
a. It will not be a normal distribution
b. The data has been entered incorrectly
c. It will be a normal distribution
d. It will have to be checked with a Levene's test
3. A researcher was interested in stress levels of lecturers during lecturers. She took the same group of 8 lecturers and measured their anxiety (out of 15) during a normal lecture and again in a lecture in which she had paid students to be disruptive and misbehave. Based on the SPSS output how would you interpret these results?
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Paired Differences
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Mean
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Std. Deviation
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Std. Error Mean
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95% Confidence Interval of the Difference
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t
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Df
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Sig (2-tailed)
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Lower
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Upper
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Pair Misbehaved -Normal 1 Lecture
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6.2500
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4.8033
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1.6982
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2.2344
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10.256
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3.680
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7
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.008
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a. Anxiety levels were significantly lower in lectures in which students misbehaved.
b. There were no significant differences between anxiety levels in normal lectures and in those in which students misbehaved.
c. Anxiety levels were significantly higher in lectures in which students misbehaved.
d. We can't tell any of the above from the output given.
4. A psychologist was interested in whether there was a gender difference in the use of email. She hypothesised that because women are generally better communicators than men, they would spend longer using email than their male counterparts. To test this hypothesis, the researcher sat by the email computers in her research methods laboratory and when someone started using email, she noted whether they were male or female and then timed how long they spent using email (in minutes). What should she report?
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Group Statistics
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Gender
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N
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Mean
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Std. Deviation
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Std. Error Mean
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Time Using Email (Day 2)
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Male
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8
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5.0000
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4.50397
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1.59239
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Female
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8
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32.0000
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40.04640
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14.15854
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Independent Samples Test
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Levene's Test for Equality of Variance
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t-test for Equality of Means
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F
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Sig.
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t
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df
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Sig. (2-tailed)
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Mean Difference
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Std. Error Difference
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95% Confidence Interval of the Difference
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Lower
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Upper
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Time Using Email (Day 2)
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Equal variances assumed
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12.999
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.003
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-1.895
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14
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.079
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-27.0000
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14.24781
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-57.55851
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3.55851
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Equal variances not assumed
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-1.895
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7.177
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.099
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-27.0000
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14.24781
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-60.52295
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6.52295
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a. Females spent significantly longer using email than males, t(7.18) = -1.90, p < .05.
b. Females spent significantly longer using email than males, t(14) = -1.90, p < .05.
c. Females and males did not significantly differ in the time spent using email, t(7.18) = -1.88, ns.
d. Females and males did not significantly differ in the time spent using email, t(14) = -1.88, ns.
5. A researcher was interested in the effects of emotion-evoking music on exam performance. Before their SPSS exam, a lecturer took one group of students to a room in which calming music was being played. A different group of students were taken to another room in which the 'death march' was being played. The students then did the exam and their marks were noted. The SPSS output is below. The experimenter made no predictions about which form of support would produce the best exam performance. What should he report?
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Group Statistics
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Emotional Support
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N
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Mean
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Std. Deviation
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Std. Error Mean
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SPSS Exam Mark
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Positive Support
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20
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65.1500
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5.0396
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1.1269
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Negative Support
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20
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57.8000
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15.2129
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3.4017
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Independent Samples Test
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Levene's Test for Equality of Variance
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t-test for Equality of Means
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F
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Sig.
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t
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df
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Sig. (2-tailed)
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Mean Difference
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Std. Error Difference
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95% Confidence Interval of the Difference
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Lower
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Upper
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SPSS Exam Mark
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Equal variances assumed
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18.117
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.000
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2.0851
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38
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.047
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7.3500
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3.5835
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9.559E-02
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14.6044
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Equal variances not assumed
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2.051
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23.121
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.052
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7.3500
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3.5835
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-6.09e-02
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14.7609
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a. Students receiving positive music before the exam did significantly better than those receiving negative music, t(38) = 2.05, p < .05.
b. Marks for students receiving positive music before the exam did not significantly differ from students receiving negative music, t(38) = 2.05, ns.
c. Students receiving positive music before the exam did significantly better than those receiving negative music, t(23.12) = 2.05, p < .05, 1-tailed.
d. Marks for students receiving positive music before the exam did not significantly differ from students receiving negative music, t(23.12) = 2.05, ns.
Data Analysis Question 1-
One of my pet peeves as a psychologist are "pop psychology" books. Often times, these books can actually do more harm than good, perpetuating stereotypes or offering advice that is not rooted in theory or research. About 10 years ago, John Gray wrote the best-selling book "Men are from Mars, Women are from Venus." Despite the fact that Gray earned his degrees from non-accredited colleges/universities and had no formal training in psychology, his book literally took the world by storm selling over 7 million copies. Psychologists have hypothesized that the book could actually be harmful to relationships and relationship satisfaction. (This next part is fictional). Dr. Smith decided she wanted to test the impact the book has on marital satisfaction. Dr. Smith took 2 groups of people who were in relationships and randomly assigned them to one of two conditions. One group read "Men are from Mars..." whereas the other read a nonfiction book about mediating relationships rooted in research. The dependent variable was an objective measure of their happiness with their relationship, given after reading their respective book. Use the dataset "Venus.sav" to analyze the data and report the following:
1. Mean, standard deviation, minimum and maximum level of happiness for each group, along with the grand mean of all participants combined.
2. State both the null and alternative hypotheses for the research question.
3. Conduct the appropriate t-test to assess whether or not there are statistically significant differences between each group.
4. Provide a short narrative of the results. Be sure to include a description of each group and whether or not the statistical test results were significant.
Data Analysis Question 2 -
Mrs. Jones, a 7th grade English teacher, believes that her student's grammar declines once they start regularly using cellphones and sending text messages. Her theory is that the abbreviated style of texting reinforces the use of poor grammatical standards. Mrs. Jones decides to collect data to test her theory. She administers a grammar test to a sample of her students that have recently received a cellphone from their parents. After a 6-months, she administers the grammar assessment again. The data is included in the file named "TextMessages.sav."
1. Report the mean, standard deviation and range of test scores for time 1 and time 2.
2. State both the null and alternative hypotheses for the research question
3. Conduct the appropriate t-test to assess whether or not there are statistically significant differences between each group
4. Provide a short narrative of the results. Be sure to include a description of each group and whether or not the statistical test results were significant.