Hello,
I would like to recommend the following enhancements to the Process Capability platform, specifically as pertains to non-normal indices (i.e., where no distribution fits and indices are calculated based on percentiles).
1. Allow calculation based on actual percentiles, separate from using a curve fit (currently, the calculation for non-parametric distributions uses Smooth Curve).
2. Allow calculation of metrics based on different percentile ranges, with suitable scaling factors based on normalizing the distribution and sample sizes, conceptually similar to what is done for robust-sigma calculations. Examples listed below.
0.00135 – 0.99865 => 1
0.005 – 0.995 => 0.859
0.05 – 0.95 => 0.548
0.1 – 0.9 => 0.427
0.25 – 0.95 => 0.225
Thanks and regards
Mehul Shroff