All the equations in this section fit frequency distributions. The X values represent Y values in the original data set, and the Y values are the frequency or cumulative frequency.
Prism can create a frequency distribution from column data, using an analysis created for that purpose (called, of course, Frequency Distribution).
A frequency distribution plots the number of observations as a function of value. A cumulative frequency distribution plots the cumulative number of observations as a function of value. Each Y value is the number of observations in the original data set that have a value less than or equal to the X value.
The Y values can be expressed as the counted number of observations, as fractions or as percentages.