After analyzing the key drivers affecting a QBs ability to score a TD, I tried to analyze their predictability. I used the NFL 2013 data (same data I used earlier) to perform this analysis as well.
Data: NFL http://on.nfl.com/1qtl2RA
I tried to determine the probability of touchdowns given each team played approximately 16 games a season. That normalizes QBs whose teams made the playoffs versus the ones that did not.
We can see from this graph that there is approximately a 12.5% chance that a QB will score 2 TDs, and 18% chance that they will score one TD. As expected the probability fo scoring more TDs has a lower probability.
Looking at the cummulative probability we see nothing surprising here.
There is a 60% probability that a QB qill score 1 or less TDs.
Reversing both the equations, to solve for "x", we can determine the number of TDs at varying levels of probability and cummulative probabilities.