Table 2.

The principle types of hypothesis test. Tests comparing more than two samples can indicate that one group differs from the others, but will not identify which. Subsequent ‘post hoc’ testing is required if a difference is found.

Type of data	Number of groups
	1 (comparison with a standard)	1 (before and after)	2	More than 2	Measured over a continuous range
Categorical	Binomial test	McNemar's test	χ2 test, or Fisher's exact (2×2 tables), or comparison of proportions	χ2 test	Logistic regression
Continuous (normal)	One-sample t-test	Paired t-test	Independent samples t-test	Analysis of variance (ANOVA)	Regression analysis, correlation
Continuous (non-parametric)	Sign test (for median)	Sign test, or Wilcoxon matched-pairs test	Mann–Whitney U test	Kruskal–Wallis test	Spearman's rank correlation