Very brief and simple descriptions. Percentile is how impressive your resume is (ignoring Margin of Victory). Pythag is how good you are. The #’s are based off of the F+ work of Bill Connelly and Brian Fremeau.
One tidbit: Had Houston gone undefeated, their Percentile would be .8632. It was a soft schedule, but not so soft that a strong team would expect to go undefeated against it.
(Edit: Fixed a big for Ohio State)