C5-08 Johnson transformation - Process Capability for Nonnormal data Lean Six Sigma

When we want to use normal capability tools but our data are nonnormal, we can transform the data to fit a normal distribution. We can use want of the following two transformations : the Box – cox and the Johnson transformation. The Box-cox transformation is fairly simple to understand but does not always work. The Johnson transformation works most of the time but is more complicated. Both attempt to transform data mathematically so the data appear normally distributed. When the Box-Cox transformation does not adequately transform our data, we can try the Johnson transformation. It selects one optimal distribution function to transform the data into normal data. .....