# Plotting position

From AMS Glossary

## plotting position

An empirical distribution, based on a random sample from a (possibly unknown) probability distribution, obtained by plotting the exceedance (or cumulative) probability of the sample distribution against the sample value.

The exceedance probability for a particular sample value is a function of sample size and the rank of the particular sample. For exceedance probabilities, the sample values are ranked from largest to smallest. The general expression in common use for plotting position is where

*r*is the ordered rank of a sample value,*n*is the sample size, and*b*is a constant between 0 and 1, depending on the plotting method.*See*California plotting position, Cunnane plotting position, Gringorten plotting position, Hazen plotting position, Weibull plotting position.