I have a Python model for football matches, and I backtested it against some data. I have a dataset of hypothetical profits / losses from the model, which I've standardised by dividing by the stake. I'm interested in getting the variance of my returns. Just simply getting a standard deviation in Excel produced a percentage > 30. I'm thinking it doesn't make sense getting the variance this way, since you can expect some returns to be quite big, when betting say on 9:1 works out. I'm also thinking of getting the variance from the Binomial Poissin Distribution. Basically my aim is to test a few hypotheses about the model, but I can't seem to get a decent estimate for variance.