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Independent Samples t Tests SPSS. Read This Article. Wuensch, K. L., & Moore, C. H. (2004). Effects of physical attractiveness on evaluations of a male employee’s allegation of sexual harassment by his female employer . Journal of Social Psychology , 144 , 207-217. . Download the Data.
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Read This Article • Wuensch, K. L., & Moore, C. H. (2004). Effects of physical attractiveness on evaluations of a male employee’s allegation of sexual harassment by his female employer. Journal of Social Psychology, 144, 207-217.
Download the Data • http://core.ecu.edu/psyc/wuenschk/SPSS/Reverse-Pattr-Guilt.sav • These data are from the research reported in the article • Bring the data into PASW/SPSS
The Variables • The grouping variable is P_Attr • 1 indicates the plaintiff was attractive • 2 indicates that he was not attractive • The test variable is Guilt • 1 = definitely not guilty • 9 = definitely guilty
The Analysis • Analyze, Compare Means, Independent Samples T Test
Download Files to Estimate Cohen’s d • Go to http://core.ecu.edu/psyc/wuenschk/SPSS/SPSS-Programs.htm • Download two files, .sav and .sps
Enter Values in .sav File • Enter “Equal Variances Assumed” statistics.
Run the Syntax File • Just click on RUN, ALL.
Write the Summary Statement • When the plaintiff was physically attractive, the jurors were significantly more certain of her guilt (M = 6.21, s = 1.81, n = 160) than when the plaintiff was not physically attractive (M = 5.52, s = 2.17, n = 164), t(314.4) = 3.08, p = .002,d = .34, 95% CI [.12, .56].
Equal Variances Assumed or Not • I followed Zimmerman’s advice and reported the “equal variances not assumed” t, because the sample sizes were not equal. • But you must always use the “equal variances assumed” t and df when using the program that estimates Cohen’s d.
SD or s • For many years, “SD” was the APA-approved symbol for standard deviation. • In the most recent Publication Manual they added “s” as appropriate to symbolize the sample standard deviation. • Only time will tell whether authors shift from “SD” to “s.”