Actually, that’s not relevant. We have to compare how many applied versus how many got accepted. And that has to include a comparison of GMAT and GPA scores.
If it can be shown that Stanford, or any other elite MBA program, rejects a higher percentage of state university students with stats similar to elite schools, then it would be strong evidence of a true advantage given to elite schools.
It is well known that students going to elite schools are highly ambitious and highly intelligent. Thus they are more likely to apply to elite graduate programs than state schools students. Yes, this means they will be overrepresented, but does not mean that it is easier for them to get into a graduate program than it is for an equally ambitious, and equally intelligent, state school student.