Box-cox transformation isn't working!?

Hi, it's me (AGAIN), another time another problem...

I've written the following code - where strength is a matrix of data [128 x 1] that has a non-normal distribution. Below I have tried to apply the box-cox transformation but it still returns the kstest as 1...what am I doing wrong!?

Thanks! :)

%%Box-cox transformation
%applying box-cox
[box_cox_strengths, lambda] = boxcox(strength);
box_cox_data = [box_cox_strengths pure_time];

[h, p] = kstest(box_cox_strengths);

Answer 1

[David Hill]

My understanding is that the boxcox() transformation changes the data into an approximately normal distribution. And the kstest() tests if the data is from a normal distribution and returns 1 if it is. Therefore, it seems that everything is working fine.

[Sophie Chumas]

Ah, might've gotten confused with interpreting the results of the kstest then! Thanks.

Although when I apply the kstest to the original non-normally distributed data, it comes out with the same answer...other people have been getting '0' returned when their distribution has been transformed by box-cox, and '1' for their initial distribution thus suggesting if it's normal, the kstest outcome is '0'??

Thanks! :)