001), however are both highly “significant”. The differences on compulsive behavior ( p =.

otherwise, report the “Equal variances not assumed” t-test results.įollowing this procedure, we conclude that the mean differences on anxiety ( p =.05, then report the “Equal variances assumed” t-test results. Which line to report depends on Levene’s test because our sample sizes are not (roughly) equal: Output I - Significance LevelsĪs previously discussed, each dependent variable has 2 lines of results. T-TEST GROUPS=divorced(0 1) /MISSING=ANALYSIS /VARIABLES=anxi depr comp anti /ES DISPLAY(TRUE) /CRITERIA=CI(.95). Since they're very useful, try and upgrade if you're still on SPSS 26 or older.Īnyway, completing these steps results in the syntax below. Sadly, the effect sizes are only available in SPSS version 27 and higher. Next, we fill out the dialog as shown below. Independent Samples T-Test Flowchart Independent Samples T-Test DialogsĪnalyze Compare Means Independen t Samples T Test Now, if that's a little too much information, just try and follow the flowchart below. More generally, this procedure is known as the Welch test and also applies to ANOVA as covered in SPSS ANOVA - Levene’s Test “Significant”. These are shown in the SPSS t-test output under “ equal variances not assumed”. If that's not the case, then you should report adjusted results. If sample sizes are not roughly equal, then Levene's test may be used to test if homogeneity is met. This is not needed if both sample sizes are roughly equal. Homogeneity of variances: both subpopulations must have equal variances on the dependent variable.Normality: the dependent variable must follow a normal distribution in each subpopulation.This often holds if each row of data represents a different person. It does, however, require some assumptions. That the entire populations are also different?Īn independent samples t-test will answer precisely that. The difference on antisocial behavior (final column) is especially large.Ĭan we conclude from these sample differences Also note that children from divorced parents have slightly higher mean scores on most tests.Note that n = 49 (parents not divorced) and n = 34 (parents divorced) for all dependent variables.means anxi to anti by divorced /cells count mean stddev.

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