Pp is calculated using the parameter values that you specify or is estimated using maximum likelihood method for a distribution used in the analysis. Minitab calculates the Pp statistic using either the Z-Score method (default) or the ISO method, depending on the settings that are selected in . The following formulas are based on the default tolerance of K = 6, which is 6 standard deviations wide (3 standard deviations on each side of the process mean).

Term | Description |
---|---|

Zlsl | Φ^{–1}(p_{1}) |

Zusl | Φ^{–1}(p_{2}) |

Φ^{–1}(p) | p * 100^{th} percentile of a standard
normal distribution |

p_{1} | Prob (X ≤ LSL) |

p_{2} | Prob (X ≤ USL) |

X | X follows the distribution used in the analysis |

Term | Description |
---|---|

USL | Upper specification limit |

LSL | Lower specification limit |

X_{0.99865} | The
99.865^{th} percentile for the specified distribution |

X_{0.00135} | The 0.135^{th} percentile
for the specified distribution |

PPL is calculated using the parameter values that you specify or is estimated using maximum likelihood method for a distribution used in the analysis. Minitab calculates the PPL statistic using either the Z-Score method (default) or the ISO method, depending on the settings that are selected in . The following formulas are based on the default tolerance of K = 6, which is 6 standard deviations wide (3 standard deviations on each side of the process mean).

Term | Description |
---|---|

Φ^{–1}(p) | p *
100^{th} percentile of a standard normal distribution |

p_{1} | Prob (X ≤ LSL) |

X | X follows the distribution used in the analysis |

Term | Description |
---|---|

LSL | Lower specification limit |

X_{0.5} | The 50^{th}
percentile for the specified distribution |

X_{0.00135} | The 0.135^{th} percentile for the
specified distribution |

PPU is calculated using the parameter values you specify or is estimated using maximum likelihood method for a distribution used in the analysis. Minitab calculates the PPU statistic using either the Z-Score method (default) or the ISO method, depending on the settings that are selected in . The following formulas are based on the default tolerance of K = 6, which is 6 standard deviations wide (3 standard deviations on each side of the process mean).

Term | Description |
---|---|

Φ^{-1}(p) | p * 100th percentile of a standard normal distribution |

p_{2} | Prob (X ≤ USL) |

X | X follows the distribution used in the analysis |

Term | Description |
---|---|

USL | Upper specification limit |

X_{0.5} | The 50^{th}
percentile for the specified distribution |

X_{0.99865} | The 99.865^{th} percentile for the
specified distribution |