I have two groups (healthy and disease, different sample sizes) of data, pooled from the individual subject's measurements of a certain region of the brain. The size of the brain region may be different from each individual and the sample sizes were different in these two groups. I have just carried out the ks.test using R on the data. They are not normally distributed.
As such, I ended up having 2500 samples for the healthy group and 1000 samples for the disease group.
I have plotted the histogram of these two groups (using normalized counts for y axis) and they appeared to be two different distributions, with overlapping. I would like to determine the cut-off value between two groups. What would be the correct way to go about it?