The Adjusted p Chart and u Chart for Varying Sample Sizes

Abstract

It is common to have control charts for fraction of nonconforming items or number of nonconformities that are based on differing sample sizes for each observation. This paper presents a simple method for charting such data that is as easy to interpret as a control chart for fixed sample size and that has the same chance for an observation to lie beyond the control limits as a control chart with limits computed separately for each observation.

• Binomial Distribution
• Poisson Distribution
• Sample Size
• Stabilized p Chart
• Stabilized u Chart

Additional information

Notes on contributors

David M. Rocke

Dr. Rocke is Professor in the Graduate School of Management. He is a Member of ASQC.