Box-Cox formula
If you use a Box-Cox transformation, Minitab transforms the original data values (Yi) according to the following formula:
where λ is the parameter for the transformation. Minitab then creates a control chart of the transformed data values (Wi). To learn how Minitab chooses the optimal value for λ, go to Methods and formulas for Box-Cox Transformation.
Common λ values
The following table shows some commonly used λ values and their transformations.
| λ | Transformation |
|---|---|
| 2 |  |
| 0.5 |  |
| 0 |  |
| −0.5 |  |
| −1 |  |
