2022 Introduction to Statistics in Research Mitchell 2nd ed

I N T R O T O R E S E A R C H : D A T A V I S U A L I Z A T I O N & C O M M O N S T A T T E S T S

But we still need to know effect size.

POST HOC TEST – TUKEY: Post hocs are also called multiple comparison tests, and follow-up test or comparisons. Essentially, post hoc tests are tests of significance of difference between groups means. It should be calculated after the overall ANOVA has shown significant difference, which it does. Tukey Honestly Significant Difference (HSD) is the best test if the assumption of homogeneity has been met. If homogeneity of variance has been violated, use the Games-Howell (in some cases, you may run multiple tests (Welch, Brown-Forsythe, etc) in cases where we have not tested for equal variance. For the one-way ANOVA, a Tukey test review the significance with the confidence interval.

Table 136: Post hoc test

• North Region is different from East and West (confidence interval does not cross zero) • South Region is different from East and West (confident interval does not cross zero) • North and South Region means are not different from each other (confidence interval crosses zero) • East and West Region means are not different from each other (confidence interval crosses zero)

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