Select the option that best describes your data.

If your data are in a single column of the worksheet, complete the following steps.

- Under Data are arranged as, select Single column.
- In Single column, enter the column of numeric data that you want to analyze.

In this worksheet, Diameter contains the diameter of piston rings.

C1 |
---|

Diameter |

74.030 |

74.002 |

74.019 |

73.992 |

73.995 |

If you have subgroups arranged in rows across several columns of the worksheet, and each row represents a single subgroup, complete the following steps.

If you use this option to enter your data, all subgroups must be the same size. If your subgroups are arranged in rows and the sizes differ, you can enter a missing value symbol "*" in worksheet cells as needed to make all the subgroup sizes the same.

- Under Data are arranged as, select Subgroups across rows of.
- In Subgroups across rows of, enter the columns of numeric data that you want to analyze.

In this worksheet, the first row contains the diameters of the piston rings in subgroup 1. The second row contains the diameters of the piston rings in subgroup 2, and so on.

C1 | C2 | C3 |
---|---|---|

Observation 1 | Observation 2 | Observation 3 |

74.030 | 73.995 | 73.988 |

74.002 | 73.992 | 74.024 |

74.019 | 74.011 | 74.021 |

73.992 | 74.004 | 74.005 |

From the drop-down list, select a nonnormal distribution to fit your data. To produce a reliable estimate of process capability, the data must follow the distribution that you select. If you are unsure which distribution best fits your data, use Individual Distribution Identification.

For more information on choosing an appropriate distribution for nonnormal data, go to Capability analyses with nonnormal data.

To perform the analysis, you must enter a lower specification limit, an upper specification limit, or both.

- Lower spec
- Enter the minimum acceptable value for the product or service. If it is not possible for measurements to fall below this value, select Boundary to define the lower specification limit as a boundary.
- Upper spec
- Enter the maximum acceptable value for the product or service. If it is not possible for measurements to exceed this value, select Boundary to define the upper specification limit as a boundary.

When you define a specification limit as a boundary, Minitab reports the expected capability indices related to the spec limit/boundary as missing values (*). Therefore, define a limit as a boundary only if it is theoretically impossible for measurements to fall beyond the limit. For example, an upper specification limit of 100% purity is a boundary because it is not possible to exceed 100% purity. A lower specification limit of 0% purity is a boundary because it is not possible to fall below 0% purity.