> That aside, isn't the difference in population between states going to cause statistical oddities with the biggest states trending to the average and the smallest being potential outliers?

I don't think so. That would be plausible if the sample sizes (not the population sizes, which are quite large) from which the average state IQs are calculated were too small in the smaller states for some reason. The population of even the least populous state [1] is relatively large.

[1]: Currently Wyoming, with an estimated population of 581,381. (https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ...)