Data types Data subtypes Examples Statistically manipulable?
Continuous Interval Date Yes - parametric tests (e.g., t-test, ANOVA)
Ratio Age Yes - parametric tests
Ordinal   Size place Yes - nonparametric tests (e.g., Chi-squared)
Nominal Coded (numbers or words) Gender code Yes - nonparametric tests
Descriptive (uncoded numbers or words) Notes, IDs No
  Note: parametric tests may be used only when the sample data follow a Gaussian distribution