Charting Murphy

Daniel Murphy went 1 for 4 in the Nationals 5-3 comeback win against the Marlins Friday night. That was enough for his batting average to remain above .400 at .405, which leads the majors.

The chance of Murphy hitting .400 for the season is slight, but this spreadsheet and chart will give you an idea of the probability as his season progresses. The longer he stays above .400, the easier the feat becomes.

Here is an explanation of the columns of the spreadsheet:

1. Game Date — Days the Nationals played.
2. Nationals Games — The total number of games the Nationals played through that date.
3. Hits — Total number of hits for Murphy through that date.
4. At Bats — Total number of at bats for Murphy through that date.
5. Batting Average — Batting average based on the two previous columns.
6. AB per game — Number of AB per Nationals game. Players don’t play every day, so basing this figure on the number of team games played assumes the hitter will miss games at a consistent rate.
7. Remaining AB — AB per game times (162- Nationals Games). Approximation of how many AB the batter has left in the season.
8. Total AB — Remaining AB + Actual AB
9. Static Prob of .400 — This is based on a fixed probability of getting a hit in an at bat. For Murphy, I used his Marcel prediction of .281, his intrinsic BA. The calculation takes the following steps:
   1. How many hits does the player need to hit .3995 in the total number at bats?
   2. How many more hits does he need to reach that number?
   3. What is the probability of picking up at least that many hits in the remaining AB given his intrinsic BA?

   That is the static probability of hitting .400.

10. Dynamic Prob of .400 — The calculation is the same as above, except I use column K, which adjusts the intrinsic batting average up as the hitter keeps his average much higher than expected.
11. Dynamic Intrinsic BA — When the number of hits is outside the 95% confidence interval of the previous days dynamic intrinsic BA, add .001 to the previous number. This is a slow adjustment to recognize that the hitter may have achieved a new talent level.
12. AB w/NoH to fall Below .400 — The 0 for needed to ball below .400.

I will update this daily until it’s clear Murphy won’t hit .400.

from baseballmusings.com http://ift.tt/1V0YhID