How to categorize data from an acoustic signal?

Hello everyone,

I have an acoustic signal(.wav) which I import to matlab using the audioread() funtion. Afterwards I take the fft() of the imported signal. Now I would like to categorize and sort the data in a way, which afterwards by plotting it I would get a cummulative (normal) distribution function. I would like to categorize the data into 8 classes.

I hope the question is understandable and thanks in advance!