Question: Provide a substantive contribution that advances the discussion in a meaningful way by identifying strengths of the posting, challenging assumptions, and asking clarifying questions.
When running an independent samples t-test on SPSS, the output includes test results for both an equal variances assumed t-test and an equal variances not assumed t-test (SPSS Tutorials, 2018). The Levene's test for equal variances (F ratio) is used to test the homogeneity assumption for using an independent samples t-test (SPSS Tutorials, 2018). When the F ratio is statistically significant, the homogeneity of variances assumption is violated (Warner, 2013). If the sig column in the SPSS output for the F ratio is greater than .05, the homogeneity of variances assumption is met and the equal variances assumed line of t-test results is reported (SPSS Tutorials, 2018). If the sig column in the SPSS output for the F ratio is less than or equal to .05, the homogeneity of variances assumption is violated and the equal variances not assumed line of t-test results may be reported by the researcher (Warner, 2013). The equal variances not assumed t-test has a smaller degrees of freedom, resulting in a more conservative test (Warner, 2013).
-Kaitlin Walmer
References: SPSS Tutorials. (2018). SPSS independent samples t-test.
Warner, R. (2013). Applied statistics: From bivariate through multivariate techniques (2nd ed.) Thousand Oaks, CA: Sage.