I was hoping someone could help, I am comparing proportional data in to two different groups. One group has a sample size of 22 and the other 530. The data are not normally distributed and have different shaped distributions. Is a Mann Whitney test OK to use for this kind of data. I have tried GLM but my residuals are very strange.
The response values are proportions of overlap in home ranges. Values from 0 (no overlap) to 1 (full overlap). I tried to fit a binomial GLM. Response was overlap, predictor was same animal (0) diff animal (1). Standardized residuals plotted for normality resulted in a s-shaped curve.
They have quite a few zero values.