One-Way ANOVA vs Kruskal-Wallis: Which Test Does Your Data Actually Need? You have one categorical grouping variable and one continuous outcome, and you want to know whether the groups differ. Two tests compete for the job: the one-way ANOVA and the Kruskal-Wallis H test. They answer the same research question, but they make very different
Two Measurements, One Question: Which Test Fits Your Data? You measured the same people twice — before and after a training course, at baseline and follow-up, under two conditions — and now you need to know whether the scores really changed. Two tests compete for this job in SPSS: the paired-samples t-test and the Wilcoxon
Your Shapiro-Wilk Test Came Back Significant. Now What? You ran the normality check and the Shapiro-Wilk test came back significant. Your histogram leans to one side and the Q-Q plot curves away from the line. If your next step is a t-test, an ANOVA, or a regression, that feels like a problem — because those
The chi-square test is the default choice for testing whether two categorical variables are related. But it relies on an approximation that breaks down when your sample is small. When one or more cells in your table have very low expected counts, the p-value chi-square gives you can be misleading. That is exactly when Fisher’s
When your data do not behave the way Pearson’s correlation expects, you do not have to abandon the question. If you want to know whether two variables move together — as one goes up, does the other tend to go up (or down)? — but your variables are ranked, skewed, or measured on an ordinal
Nonparametric tests answer a question every SPSS user asks sooner or later: your data do not meet the assumptions of a t-test or ANOVA, so what do you run instead? This guide gives you the decision, not just a list of test names. Work through the questions below, find your situation, and you will land
Kruskal–Wallis H Test in SPSS: How to Run and Interpret It If you have three or more independent groups and your data does not meet the assumptions of a one-way ANOVA, the Kruskal–Wallis H test is the nonparametric test you reach for. It compares the distributions of the groups without assuming normality, and it is
When to Use the Wilcoxon Signed-Rank Test You have the same people, items, or matched pairs measured twice — before and after an intervention, pre-test and post-test scores, or two ratings of the same thing — and you want to know whether the scores systematically changed. The paired-samples t-test is the usual first choice for
Introduction You have two independent groups and one problem: your data are not suitable for an independent-samples t-test. Maybe the scores are ordinal, like Likert-scale ratings. Maybe the distribution is heavily skewed, or your sample is small and normality looks shaky. This is exactly where the Mann–Whitney U test earns its place. The Mann–Whitney U