Cheatsheet

370. Cheatsheet

Index	Formula	Variation Used	Assumes Process Centering	Measures
$𝐶_{𝑝}$	$\frac{USL - LSL}{6 𝜎_{within}}$	Short-term ( $𝜎_{within}$ )	Yes	Pure “noise” under stable conditions (same machine, same operator, same material, no maintenance events)
$𝐶_{𝑝 𝑘}$	$min (\frac{USL - 𝜇}{3 𝜎_{within}}, \frac{𝜇 - LSL}{3 𝜎_{within}})$	Short-term ( $𝜎_{within}$ )	No	Pure “noise” under stable conditions (same machine, same operator, same material, no maintenance events)
$𝑃_{𝑝}$	$\frac{USL - LSL}{6 𝜎_{overall}}$	Long-term ( $𝜎_{overall}$ )	Yes	Real-life variability from all causes (data across multiple shifts, operators, material batches, maintenance)
$𝑃_{𝑝 𝑘}$	$min (\frac{USL - 𝜇}{3 𝜎_{overall}}, \frac{𝜇 - LSL}{3 𝜎_{overall}})$	Long-term ( $𝜎_{overall}$ )	No	Real-life variability from all causes (data across multiple shifts, operators, material batches, maintenance)
$𝐶_{𝑝 𝑚}$	$\frac{USL - LSL}{6 \sqrt{𝜎_{within} + {(𝜇 - 𝑇)}^{2}}}$	Short-term ( $𝜎_{within}$ ) Deviation from target ( $𝑇$ )	No	Penalizes deviation from target ( $𝑇$ ); reflects capability under stable conditions when target matters

Centered v. Decentered Process