What would the Null Hypothesis be for predicting sports outcomes?

kovy

New Member
#1
So I made a program to predict the outcome of baseball games, as either a W or a L for the home team. I want to know if my program and algorithm are actually having an effect or is it just luck. I thought at first that it would be the likelihood of seeing how many times I was correct and seeing how likely that was. For that, I thought to do .5^n where n is the number of correct predictions I got. But I feel like that is not the correct way to do it as teams do not always have 50/50 odds to win. Also, that felt incorrect because they may not all be in a row. So I thought that maybe I should do the number of times my odds lined up with betting odds. But I dont know what the probability of me getting withing 5% of the professional odds are.

My question is what would the null hypothesis be? Would it be based on # correct or # of times my odds lined up with the odds for that game?
 
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#2
Hi,
Would it make sense to test the one sample proportion of correct outcomes against nullhypothesis H0: po=0.5, using a normal distribution with one tail?

zobs=(x-n*po)/sqrt(n*po*(1-po))

where
x:correct predictions
n:number of observations
po=0.5

for the one tailed hypothesis test p > p0, the resullt is significant if zobs > z(1−alpha) alpha: significance level.

The outcomes of the games might not be rated as 50/50, but from what i understand, the p0=0.5 here tests the accuracy of the algorithm, which will approach being correct 50% of the time if it doesnt work, given enough samples.

interesting project, will you let me know the result of the hypothesis test if you decide to do it that way?
 
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#4
a common sigificance level is usually alpha=0.05
so if your zobs>z(1-alpha), at alpha=0.05, it means that you are 95% certain that it is not just due to chance.

z(1-0.05) = 1.644854, this is your critical value for the one tailed hypothesis test. if zobs is larger than that, the result is significant.

i welcome others to chime in if they spot something here that doesnt make sense :)