Type of data | Type of chart | Centre line | Three-sigma control limits |

Continuous data (x) of which there are n items | x-chart | ||

mr-chart | |||

Proportion data (p) given by x/n where x is the number of occurrences and n is its number of opportunities. | p-chart | ||

Count data (u) with n observations each in a known “area of opportunity” n_{i} | u-chart | ||

Count data (c) with n observations each with a constant “area of opportunity” | c-chart |