A colleges’s admit rate is not a probability of admission. The applicants are not identical in attributes, like identically shaped playing cards in a deck. Applicants do not each have identical desirability to a school.
A college’s admit rate is like the average number of gazelles that lions in Africa kill on the savannah. A strong, fast lion will catch a gazelle almost every time, just like Malia Obama will get admitted into just about every school she applies to. A slow, weak lion will almost never catch a gazelle. College admit rates are the aggregated outcomes of slow lions and fast lions.
So is the likelihood of getting into harvard related to the likelihood of getting into stanford? Are you a slow lion or a fast lion? Are you Malia’s little sister?