It wouldn't surprise me if a very large majority of YC applicants did NOT go to the Ivy League.

Regardless of whether students/graduates of those schools are smarter, from what I've heard there is much less of an entrepreneurial spirit in the Ivies.

If anything, I would think YC has a bias towards schools like MIT, Berkeley, CalTech, Stanford, UIUC, etc., none of which are in the Ivy League.

(And by bias I don't mean an admissions bias, simply that a greater percentage of accepted teams go to these schools)