p-Chart Control Limits: Variable Sample Size, 3-Sigma Formulas, and Laney p-Prime
Step-by-step calculation of p-chart control limits with a worked PCB inspection example. Covers the variable sample size problem (exact, average-n, and standardized approaches), the np>=5 minimum, and the Laney p-prime chart for overdispersion.
control chartsworked exampleattribute charts