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BRIAN ORENG
BRIAN ORENG

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Parametric tests and non-parametric tests

Parametric tests assume data follow a defined distribution, such as a normal distribution, while relying on population parameters. On the other hand non non-parametric tests have no biases on the distribution of the data.

Some of the common parametric tests include

  • One-sample t-test: Tests if the mean of a single group is equal to a known mean.
  • Two-sample t-test: Compares the means of two independent groups.
  • Paired t-test: Compares means from the same group at different times.
  • ANOVA (Analysis of Variance): Compares means among three or more groups.
  • Z-test: Tests if there is a difference between sample and population means when sample size is large.

Common non-parametric tests

  • Mann-Whitney U test: Compares differences between two independent groups when the dependent variable is either ordinal or continuous, but not normally distributed.
  • Wilcoxon signed-rank test: Compares two related samples, matched samples, or repeated measurements on a single sample to assess whether their population mean ranks differ.
  • Kruskal-Wallis H test: Non-parametric alternative to ANOVA.
  • Chi-square test: Tests relationships between categorical variables.

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