Individual Distribution Identification - Box-Cox Transformation
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Stat > Quality Tools > Individual Distribution Identification > Box-Cox

Use a Box-Cox transformation to transform your data to follow a normal distribution and store the transformed data for further analysis. Minitab performs the Box-Cox transformation by default when it attempts to fit each of the 14 distributions and the 2 transformations or when you choose Box-Cox transformation from the drop-down list of distributions.

By default, Minitab rounds the lambda value to 0.5, -0.5, or the nearest integer. If you do not want to use rounded values for lambda, see Tools > Options > Control Charts and Quality Tools > Other.

If the Box-Cox transformation does not adequately transform your data, the Johnson transformation may work better; use whichever normal transformation method works better for your data.

Dialog box items

Box-Cox power transformation (W=Y**Lambda)

Use optimal lambda: Choose to allow Minitab to estimate the optimal lambda value.

Lambda = 0 (ln): Choose to use zero as the lambda value for a natural log transformation.

Lambda = 0.5 (square root): Choose to use 0.5 as the lambda value for a square root transformation.

Other (enter a value between -5 and 5): Choose to enter your own lambda value, then enter a value.

Store transformed data in

Single columns: Choose to store data in one column, then enter a column.

Subgroups across rows of: Choose to store data in subgroups arranged in rows across several columns, then enter the columns