One-way ANOVA

The chapter discusses the purposes, requirements, and assumptions of one-way ANOVA analysis. One-way ANOVA is used to identify the significant mean differences for more than two groups on a dependent variable with an interval or ratio-scaled variable. This chapter also includes a section on data transformation, discussing how to generate a summation score. The details of running one-way ANOVA using SPSS are shown. Guidelines to interpret the outputs of one-way ANOVA analysis, post hoc comparison, and effect sizes are presented. The assumptions on both the test of homogeneity of variance and the normality test are discussed, with the support of a normal P-P plot. In case the data is not distributed normally, the transformation methods can be applied. The example of writing a report and the means plot is presented.