• Quality of fit is a statistical test that attempts to determine whether a set of observed values match those expected within the applicable model.

  • They can show you if your sample data matches the expected data set from a normally distributed population.
  • There are several types of goodness-of-fit tests, but the most common is the chi-square test.
  • The chi-square test determines if there is a relationship between categorical data.
  • The Kolmogorov-Smirnov test determines whether a sample comes from a specific population distribution.