Frequency is the number of values in a class. A class is a segment within a population.

Relative frequency

A histogram graphs frequencies in classes spanning the data set.rT2

Frequency distribution (class sizes) can be determined subjectively, but Sturge’s Rule can compute it automatically:

Number of classes and their ranges

  1. Shin Takahashi, The Manga Guide to Statistics (San Francisco: No Starch Press, 2009). (See notes.)