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Form Class Intervals

Create a categorical variable whose levels are class intervals of a numeric variable. For example, take age and create age.f with levels {"{0,20]", "(20,60]", "(60,110]"}.

Go to Variables > Numeric Variables > Form class intervals.

Options​

  • Variable: Select the numeric variable to convert.
  • Number of intervals: Choose how many intervals to divide the variable into.
  • Method: Select how the intervals are determined:
    • Equal width: All intervals have the same range (e.g., 0–20, 20–40, 40–60).
    • Equal count: Each interval contains approximately the same number of observations.
    • Specified: Manually define the breakpoints between intervals.
  • Format: Choose whether intervals are displayed as (open, closed] or [closed, open).
  • Custom labels: Optionally provide descriptive names for each interval (e.g., "young", "middle-aged", "senior") instead of the numeric ranges.

The new categorical variable is added to the dataset alongside the original numeric variable.