figure - histogram depicting developer income distribution after log transform thus we can clearly see that the original developer income distribution that was right skewed in figure - is more gaussian or normal-like in figure - after applying the log transform ox-cox transform let' now look at the box-cox transformanother popular function belonging to the power transform family of functions this function has prerequisite that the numeric values to be transformed must be positive (similar to what log transform expectsin case they are negativeshifting using constant value helps mathematicallythe box-cox transform function can be defined asi xl - for , ilog for th such that the resulted transformed output is function of input and transformation parameter such that when the resultant transform is the natural log transformwhich we discussed earlier the optimal value of is usually determined using maximum likelihood or log-likelihood estimation let' apply the box-cox transform on our developer income feature to do thisfirst we get the optimal lambda value from the data distribution by removing the non-null values using the following code