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Adjusted r-squared

Adjusted R-squared is a regression goodness-of-fit statistic that modifies R-squared to account for the number of predictors and the sample size.

How 3 Manning books explain it

Effective Data Analysis

Adjusted R-squared is a version of R-squared that penalizes the score for additional variables included in a model.

How it is used
Uses adjusted R-squared to weigh regression fit against the complexity introduced by additional predictors.
How deep it goes
Defines the adjustment and interprets reported scores, without deriving its formula.
Examples
Uses housing-price and daily rat-sighting regressions to compare adjusted R-squared with R-squared in model summaries.
What you can do after
Evaluate/understand whether added regression predictors improve fit enough to offset their complexity, while checking other diagnostics.

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Statistics Every Programmer Needs

Adjusted R-squared is a version of R-squared that penalizes a regression model for including additional predictors.

How it is used
Balances explanatory power and model complexity when evaluating regression fit or comparing models with different predictor sets.
How deep it goes
Explains the predictor penalty and model-reduction rationale but does not provide the adjusted R-squared formula.
Examples
Uses marathon Stage 1 and Stage 2 running times, fitted values, sums of squares, and a regression with R-squared near 0.575.
What you can do after
Evaluate regression models and diagnose unnecessary predictors by comparing R-squared with adjusted R-squared.

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Statistics Slam Dunk

Adjusted R-squared is a regression-fit statistic that estimates explained response variance while accounting for the number of predictors.

How it is used
Evaluates regression fit while discouraging unnecessary predictors in NBA win models.
How deep it goes
Defines the complexity adjustment and interprets outputs, but stops short of deriving the formula.
Examples
Interprets adjusted R-squared values of 0.14 for fit1 and 0.16 for the reduced fit2 NBA wins regression.
What you can do after
Evaluate competing regression models by balancing explained variance against predictor count.

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Related concepts

These guides are generated from the text of Manning books by Manning's knowledge graph and link to the sections they draw on. The full books are available on liveBook and at manning.com.