P Chart / Laney P′
Compare a traditional P chart with Laney P′ to see how over/under-dispersion changes the control limits.
Your data
Two columns lot;result, one unit per row (0 conforming, 1 nonconforming). The baseline lots estimate p̄ and Sigma Z.
CSV/TXT without a header or pasted from Excel. Separator: semicolon or TAB; decimal separator: dot or comma. Maximum 200 observations in total, not 200 per group. Data is processed in the browser and is not uploaded to the server.
About the calculation
The P chart uses the binomial model. Laney P′ keeps p̄ but adjusts dispersion through Sigma Z estimated from baseline z-scores. Compare both before choosing a monitoring method.
Calculations run locally in the browser. Statistical distributions and functions use jStat 1.9.6; values are rounded only for display. For method selection, conditions of use and interpretation criteria, see the “Sources and methodological alignment” section above and any customer-specific requirements.
Ready for your data
Upload a dataset or use the example, then click “Calculate results”. Results will include charts, values and interpretation conditions.