University of Minnesota, Twin Cities School of Statistics
This web page implements a playoff probability calculator. Given assumptions about the probabilities for single games, it calculates probabilities for a 5 or 7 game series.
To check out what it does, just click the
submit button below.
Ignore everything but the last six lines, which will look something like
Rweb:> cat("currently,", n1, w1, n2, w2, "\n") currently, Yankees 2 Twins 1 Rweb:> cat("probability", n1, "win series:", p1total, "\n") probability Yankees win series: 0.7525 Rweb:> cat("probability", n2, "win series:", 1 - p1total, "\n") probability Twins win series: 0.2475
To modify what it does, look at the section on modifying the calculation below.
The whole calculation is determined by 5 numbers, which are assigned in the statements at the top of the web form and which you can edit.
ngame <- 7 # number of games in the series w1 <- 0 # number of wins, team 1 w2 <- 1 # number of wins, team 2 p1home <- 0.55 # probability of team 1 win at home p1road <- 0.45 # probability of team 1 win on road
The meaning of these numbers is as follows.
ngameis the number of games in the whole series (including games already played), right now only 5 or 7 is allowed.
w1is the number of wins for team 1 in the games already played. Team 1 is the team with home field advantage in the series (the team at home in the first game).
w2is the number of wins for team 2 in the games already played.
p1homeis the probability of team 1 winning a game at home. The default (
0.55) is about right for two evenly matched baseball teams (the home field/court advantage is much higher in basketball).
p1roadis the probability of team 1 winning a game on the road. The default (
0.45) is about right for two evenly matched baseball teams (the home field/court advantage is much higher
Basically, your opinion only enters the two numbers
p1road. If you don't believe the teams are evenly matched,
change these numbers and see what happens.
You can also edit the team names, but this doesn't affect any calculated numbers.
n1 <- "Angels" # name of team 1 n2 <- "Giants" # name of team 2