Select the method or formula of your choice.

- when i v
- when i > v

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

v | number of sample means that are averaged |

μ | process mean |

k | parameter for Test 1. The default is 3. |

σ | process standard deviation |

n_{i} | size of subgroup i |

The center line represents the process average. Minitab uses to estimate *μ*.

- when
- when

- when
- when

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

n_{i} | size of subgroup i |

v | number of sample means that are averaged |

μ | process mean |

k | parameter for Test 1. The default is 3. |

σ | process standard deviation |

If you use a Box-Cox transformation, Minitab transforms the original data values (*Y _{i}*) according to the following formula:

where *λ* is the parameter for the transformation. Minitab then creates a control chart of the transformed data values (*W _{i}*). To learn how Minitab chooses the optimal value for

The following table shows some commonly used *λ* values and their transformations.

λ | Transformation |
---|---|

2 | |

0.5 | |

0 | |

−0.5 | |

−1 |