In addition what the fellow monks advised above already, you do calculate the mean and the standard deviation of each category many times. You can save some time by doing it only once and store the results (e.g. while loading the data). You could also standardize your data (by subtracting the mean and dividing by the standard deviation) which also takes out the repeated calculation of mean and standard deviation in your nested loop.

In reply to Re: Improving the Nested For Loop by hdb
in thread Improving the Nested For Loop by Anonymous Monk

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