Is that really going to tell you much other than who had the most attempts. Those 3 happened to be the first 3 I checked for median, but I'd imagine most players (with a reasonable amount of carries) will have a median of 3. So your most likely going to end up a list ranked in order of rushing attempts.
You probably actually want to look at variance. Assuming high variance is bad, value players based on total yards minus some penalty for high variance. You could calculate variance by carry (home run hitters probably have high variance, plodders low variance) and by game (a high game variance player is unreliable against stronger defenses ... a boom or bust type player). You could also look at the variance in the number of carries per game. You might want to stay away from players that only see the ball a lot in games when the running game is working well (gameplan type RBs). Ideally you'd want the guy with the most consistent production, which means consistent touches game to game, consistent ypc and touchdowns spread out throughout the season. But these guys all get drafted really early (Foster, Rice, Peterson, MJD).
