What-If and Scope

Honest Capability Scope

Cp and Cpk here are deterministic arithmetic, not a statistical proof.

highlighted = computed this step

Deterministic Snapshot

This snapshot uses fixed specs, fixed mean, and fixed sigma.

Cp=5/3base Cpk=4/3what-if Cpk=5/3\text{Cp} = 5/3\quad\text{base Cpk} = 4/3\quad\text{what-if Cpk} = 5/3
Capability snapshotThe chart compares the base mean with the centered what-if.process capability Cp and CpkCp 5/3; Cpk 4/3; sigma 2measurevaluemeaningspec width20USL minus LSLsix-sigma width12six times sigmaCp5/3width comparisonCpu4/3upper sideCpl2lower sideCpk4/3smaller sidebaseLSL 40USL 60mean 52Cpu 4/3; Cpl 2what-ifLSL 40USL 60mean 50Cpu 5/3; Cpl 5/3Cp 5/3base Cpk 4/3what-if Cpk 5/3what-if Cpk 5/3; gain 1/3deterministic process-capability arithmetic only

Honesty Note

This is deterministic process-capability arithmetic only. It does not prove normality, estimate defect probability, validate the sample, identify root causes, or prove a process improvement.

capability arithmetic is not a defect-probability proof\text{capability arithmetic is not a defect-probability proof}
Capability snapshotThe chart compares the base mean with the centered what-if.process capability Cp and CpkCp 5/3; Cpk 4/3; sigma 2measurevaluemeaningspec width20USL minus LSLsix-sigma width12six times sigmaCp5/3width comparisonCpu4/3upper sideCpl2lower sideCpk4/3smaller sidebaseLSL 40USL 60mean 52Cpu 4/3; Cpl 2what-ifLSL 40USL 60mean 50Cpu 5/3; Cpl 5/3Cp 5/3base Cpk 4/3what-if Cpk 5/3what-if Cpk 5/3; gain 1/3deterministic process-capability arithmetic only