16.7: Critical Values for Grubb's Test
- Page ID
- 127261
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The following table provides critical values for \(G(\alpha, n)\), where \(\alpha\) 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 Gij 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 critical values for G given here are for a single outlier, G10, where
\[G_\text{exp} = G_{10} = \frac {|X_{out} - \overline{X}|} {s} \nonumber\]
The suspected outlier is rejected if Gexp is greater than \(G(\alpha, n)\).
| \(\frac {\alpha \ce{->}} {n \ce{ v }}\) | 0.05 | 0.01 |
| 3 | 1.155 | 1.155 |
| 4 | 1.481 | 1.496 |
| 5 | 1.715 | 1.764 |
| 6 | 1.887 | 1.973 |
| 7 | 2.020 | 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 |