How Not To Handicap A Prop Bet

I still can't believe Barnwell actually wrote this:

What will the jersey number be of the first player to score a touchdown?
Over 80.5: EVEN
Under 80.5: -120

Few things have made me question my life decisions more than putting together a spreadsheet to answer this question. But I did it, taking every player who has scored for these two teams this year, removing guys who aren't going to play on Sunday, adjusting for the games they played in and missed. It was so fucking stupid on so many levels. But I did it. And in the end, I got an expected number of … 64.4. Great, so an offensive lineman is likely to score on Sunday! In reality, it just suggests that the running backs for the teams are likely a little undervalued here, and that logic only goes further with a possibly-limited Gronkowski (number 87). Go under here, but realize that we're all losers for playing.

I have no interest in legitimately handicapping this (I guess that makes two of us), so I just adjusted the numbers for people listed at Pinny to make them fit to "an expected number of ... 64.4":

As noted, the weighted average of these is 64.4. Based on this information, Bill Barnwell recommended the under. Hopefully the reason that this is horrendous analysis is really obvious.

If you do this really sophisticated thing called adding, however, you get 48.5% for the under. With the exact same data set. With a line of -120. So an ROI of -11.1%. Sometimes referred to as lighting money on fire. While, based on that same (made up) data, the other side is +EV, with a 51.5% bet being offered at +100.

I don't really have a point to close with here, so: