List of statistical tests


Statistical tests are used to test the fit between a hypothesis and the data. Choosing the right statistical test is not a trivial task. The choice of the test depends on many properties of the research question. The vast majority of studies can be addressed by 30 of the 100 or so statistical tests in use.

Explanation of properties

  • Scaling of data: One of the properties of the tests is the scale of the data, which can be interval-based, ordinal or nominal. Nominal scale is also known as categorical. Interval scale is also known as numerical. When categorical data has only two possibilities, it is called binary or dichotomous.
  • Assumptions, parametric and non-parametric: There are two groups of statistical tests, parametric and non-parametric. The choice between these two groups needs to be justified. Parametric tests assume that the data follow a particular distribution, typically a normal distribution, while non-parametric tests make no assumptions about the distribution. Non-parametric tests have the advantage of being more resistant to misbehaviour of the data, such as outliers. They also have the disadvantage of being less certain in the statistical estimate.
  • Type of data: Statistical tests use different types of data. Some tests perform univariate analysis on a single sample with a single variable. Others compare two or more paired or unpaired samples. Unpaired samples are also called independent samples. Paired samples are also called dependent. Finally, there are some statistical tests that perform analysis of relationship between multiple variables like regression.
  • Number of samples: The number of samples of data.
  • Exactness: A test can be exact or be asymptotic delivering approximate results.

    List of statistical tests

Test nameScalingAssumptionsDataSamplesExactSpecial case ofApplication conditions
One sample t-testintervalnormalunivariate1NoLocation test
Paired difference testpaired2Location test
Unpaired t-testintervalnormalunpaired2NoLocation testHomoscedasticity
Welch's t-testintervalnormalunpaired2NoLocation test
Paired t-testintervalnormalpaired2NoLocation test
F-testintervalnormalunpaired2
Z-test intervalnormalunivariate1Novariance is known
Z-test intervalnormal2Novariances are known
Permutation testintervalnon-parametricunpaired≥2Yes
Kruskal-Wallis testordinalnon-parametricunpaired≥2Yessmall sample size
Mann–Whitney testordinalnon-parametricunpaired2Kruskal-Wallis test
Wilcoxon signed-rank testintervalnon-parametricpaired≥1Location test
Sign testordinalnon-parametricpaired2
Friedman testordinalnon-parametricpaired>2Location test
testnominalnon-parametricNoContingency table,
sample size > ca. 60,
any cell content ≥ 5,
marginal totals fixed
Pearson's testnominal/ordinalnon-parametricNo test
Median testordinalnon-parametricNoPearson's test
Multinomial testnominalnon-parametricunivariate1YesLocation test
McNemar's testbinarynon-parametricpaired2YesCochran's test
Cochran's testbinarynon-parametricpaired≥2
Binomial testbinarynon-parametricunivariate1YesMultinomial test
Siegel–Tukey testordinalnon-parametricunpaired2
Chow testintervalparametriclinear regression2NoTime series
Fisher's exact testnominalnon-parametricunpaired≥2YesContingency table,
marginal totals fixed
Barnard's exact testnominalnon-parametricunpaired2YesContingency table
Boschloo's testnominalnon-parametricunpaired2YesContingency table
Shapiro–Wilk testintervalunivariate1Normality testsample size between 3 and 5000
Kolmogorov–Smirnov testinterval1Normality testdistribution parameters known
Shapiro-Francia testintervalunivariate1Normality testSimplification of Shapiro–Wilk test
Lilliefors testinterval1Normality test