# Appendix 07: Critical Values for Grubb’s Test

- Page ID
- 6643

The following table provides critical values for *G*(α, *n*), where α is the probability of incorrectly rejecting the suspected outlier and *n* is the number of samples in the data set. There are several versions of Grubb’s Test, each of which calculates a value for *G*_{ij} where *i* is the number of suspected outliers on one end of the data set and *j* is the number of suspected outliers on the opposite end of the data set. The values given here are for *G*_{10}, where

\[G_\ce{exp} = G_{10} = \dfrac{|X_\ce{out} - \overline{X}|}{s}\]

The suspected outlier is rejected if *G*_{exp} is greater than *G*(α, *n*).

α⇒ | 0.05 | 0.01 |
---|---|---|

⇓n |
||

3 | 1.155 | 1.155 |

4 | 1.481 | 1.496 |

5 | 1.715 | 1.764 |

6 | 1.887 | 1.973 |

7 | 2.202 | 2.139 |

8 | 2.126 | 2.274 |

9 | 2.215 | 2.387 |

10 | 2.290 | 2.482 |

11 | 2.355 | 2.564 |

12 | 2.412 | 2.636 |

13 | 2.462 | 2.699 |

14 | 2.507 | 2.755 |

15 | 2.549 | 2.755 |