I suspect we will be surprised to learn that NROTC scholarship awardees have higher average stats than do the Appointees to the USNA. There are two primary reasons: 1) NROTC does not have to accomodate DI athletes, and 2) NROTC does not have to accomodate geographic and/or MOC Principal Nominees.
This is purely an anecdotal observation: when I view the stats of NROTC awardees who have posted on this website in the past couple of years, their academic stats are significantly higher than the average academic stats posted on the USNA class profile page.