# Am I using the correct model?

I'm new to statistics.

1. What type of model should be used to predict a basketball team's winning percentage? I am currently using a multiple linear model, but the residual vs. predicted plot shows my data points clustered in a circle. I standardized my explanatory variables since they were either percentages or totals.

2. Also, what model should be used for the Pythagorean Expectation formula? I would like to see what that would look like in R.

Thanks!

• I think for starters you may want to consider a logistic or a probit regression where you dependent variable is a basketball team's winning percentage. The Wikipedia articles on both subjects are quite good starting points. – usεr11852 says Reinstate Monic Jan 12 '14 at 14:03
• Are you sure? A win percentage is continuous and can take on more than 2 different values. For both of those models, it suggests usage when dependent variables are binary, e.g. take on a value of 0 or 1. – user2205916 Jan 12 '14 at 14:21
• Even though win percentage is continous, your dependant variable (did they win or not) is not - it can be either 0 (lose) or 1 (win) (what you do with ties is up to you). Using a logistic regression or linear probability model would probably be your best bet. Then predict from the estimated model. – ltronneberg Jan 12 '14 at 16:03
• @ltronneberg The dV will be a proportion if you have a time series or some other aggregated form of data. In that case you could take the log of the dV and then use a linear model instead of logit or probit. – tomka Jan 12 '14 at 16:05
• @Itronneberg Thanks for that explanation. I will go with logistic. – user2205916 Jan 12 '14 at 16:21