Prevalence

People with disease may differ from those without the disease in other ways, for example, sex.

But you can't assume from evidence like this that only females would get the disease: you'd need much bigger numbers to feel confident about that.

If the numbers get big enough, it is apparent that the disease is commoner in women, but men can still get it Ð like breast cancer.

There are any number of variables that need to be taken into account, typically: age, sex, class, ethnic group, geographical location and so on.