## Calculation of Capability Indexes

All capability indices calculations are based on estimates of the standard deviation of the process. There are several formulae that can be applied to the data for the purpose of estimating the standard deviation. Control chart estimates are based on within subgroup variation and are dependent on the order of measurement. The sample standard deviation is based only on the distribution of the data. This estimate is not affected by the measurement sequence.

- Sample Standard Deviation

- Estimates of Standard Deviation Based on Control Charts

- Calculating Capability Indexes

- Control Chart Estimated Standard Deviation Constants