What you expect and what is reality are two different things.    Eg:   What if left handedness were in some way linked to the genes for blue eyes?    In that case your expectations would be wrong.

In addition, your University example is similarly flawed.    It's very possible that out of a class of 150 (male and female CS majors) NONE of them are considered "exceptional" despite your "expectations."

When a group is filtered out of the general population according to certain attributes this filtering alone would mean they deviate from the average.

In short:   You don't assume expectations are correct - you need to prove they are correct.     That's the basis for "science".