Methods and formulas for graphs in Poisson Capability Analysis

U Chart

For information on the methods used to create the U chart, go to Methods and formulas for U Chart.

Cumulative DPU

The number of plot points equals the number of samples in your study.

The cumulative DPU for the jth sample is calculated as follows:

The reference lines on the plot are calculated as follows:

For more information on the confidence bounds, go to Methods and formulas for confidence intervals and bounds in Poisson Capability Analysis.


DiNumber of defectives in the ith sample
NiThe ith sample size