p chart

control chart for the proportion defective

UCL = p̄ + 3·√(p̄(1 − p̄)/n)

An attribute control chart for the share of defective units in samples that may vary in size. Its sister chart, the np chart, plots the number of defectives for a constant sample size.

Calculate it

Attribute Control Charts: p, np, c and u charts for defectives and defects, including variable sample sizes.

Related terms

• c chart and u chart: control charts for the number of defects