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Coefficient of determination

As explained in Statistics Slam Dunk

R2, or the coefficient of determination, is the proportion of variation in a response explained by a regression model.

R² measures the proportion of variation in a regression response explained collectively by its predictors. Values range from 0 to 1: 0 explains none of the variation, while 1 explains it all. section 5.7.3

Predicting NBA wins

For the fit1 model, glance(fit1) returns R² = 0.202 and adjusted R² = 0.137. The predictors therefore explain about 20% of variation in regular-season wins, but the adjusted measure suggests about 14% after accounting for model complexity. The model’s average absolute prediction error is 8.27 wins. section 5.7.3

How Statistics Slam Dunk covers it

How deep it goes
Defines R² and adjusted R², interprets output, and stops short of deriving their formulas.
Examples
Uses an NBA wins model, broom output, fitted wins, and an average absolute error of 8.27 wins.
What it assumes
Assumes a fitted regression model with a response and predictors, while defining R² before interpreting it.
What you can do after
Evaluate regression fit with broom’s glance() output and distinguish raw R² from adjusted R².
How it connects
Connects regression models with predictors, adjusted R-squared, p-values, fitted values, and prediction error.

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This explainer was generated by Manning's knowledge graph from the text of Statistics Slam Dunk. The section links point to the parts of the book it draws on.