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Statistics vocabulary · Hypothesis Testing

Nonparametric test

Meaning in statistics, with examples

nounCommon term

In statistics, nonparametric test means: A test that does not assume the data follow a specific distribution such as the normal, often working with ranks instead of the raw values.

In Turkish: parametrik olmayan test, nonparametrik test

How it is used

Used for small samples, ordinal data or clearly non-normal data. Common examples are the Mann–Whitney U test (instead of an independent t-test), the Wilcoxon signed-rank test (instead of a paired t-test) and the Kruskal–Wallis test (instead of a one-way ANOVA). Also spelled 'non-parametric'.

Example sentences

  1. Since reaction times were heavily skewed, we used a nonparametric test.

  2. The Kruskal–Wallis test is the nonparametric alternative to a one-way ANOVA.

Common collocations

  • nonparametric alternative
  • Mann–Whitney U test
  • rank-based test
  • nonparametric methods
  • t-testA hypothesis test that compares means: one group's mean with a fixed value, the means of two independent groups, or two measurements of the same people.
  • ANOVAShort for analysis of variance: a family of tests that compare the means of three or more groups at once by comparing variation between the groups with variation within them.
  • assumptionA condition that must hold, at least approximately, for a statistical test or model to give valid results, such as normality, equal variances or independent observations.
  • normal distributionA symmetric, bell-shaped distribution in which most values cluster around the mean and become rarer further away from it; its mean, median and mode are equal.
  • medianThe middle value when the data are put in order from smallest to largest; with an even number of values, it is the mean of the two middle ones.

More terms: Hypothesis Testing

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