# Cumulative frequency distribution

## Description

Creates a cumulative frequency distribution graph (Cumulative frequency polygon and/or cumulative dot plot).

A cumulative frequency distribution is the cumulative form of a frequency distribution.

## Required input

- Select the variable of interest.
- Optionally select a filter to include a subset of cases.

### Graph options

- Show Normal distribution: option to have a cumulative Normal distribution curve displayed together with the cumulative distribution of the data. The cumulative Normal distribution (with Mean and Standard Deviation of the data represented in the graph) curve is displayed as a smooth line. When this option is selected the cumulative frequency distribution (Cumulative frequency polygon and/or Cumulative dot plot) is plotted using a different algorithm, allowing better visual comparison of the observed frequency distribution with the theoretical Normal distribution.
- Plot all data points: option to show all individual observations.
- Complementary cumulative frequency: select this option to obtain the complementary cumulative distribution function (CCDF). Whereas the Cumulative distribution function goes from 0 to 100%, the complementary cumulative distribution goes from 100% to 0.

## Literature

- Altman DG (1991) Practical statistics for medical research. London: Chapman and Hall.