Linear Regression – (R – Squared and Adjusted R – Squared)


R- Squared and Adjusted R-Squared

Table Of Contents:

  1. What Is R-Squared Value?
  2. Formula For R-Squared Value.
  3. Interpretation Of R-Squared Value.
  4. Example Of R-Squared.
  5. Key Points To Note.
  6. Conclusion.

(1) What Is R-Squared Value?

  • R-squared, also known as the coefficient of determination, is a statistical measure that shows how well the independent variable(s) in a regression model explain the variability of the dependent variable.
  • It provides an indication of the model’s goodness of fit.

(2) Formula For R Squared Value

(3) Interpretation Of R-Squared

(4) Example Of R-Squared

(5) Key Points To Note

(6) Conclusion

(7) Adjusted R-Squared

  • Adjusted R-squared is a modified version of the traditional R-squared that accounts for the number of independent variables (predictors) in a regression model.
  • Unlike R2, which always increases as more predictors are added to the model, Adjusted R-squared penalizes the model for adding predictors that do not improve the model significantly.

(8) Formula For Adjusted R-Squared

(9) Why Use Adjusted R-Squared?

(10) Key Points Of Adjusted R-Squared?

  • Penalty for Extra Variables:

    • Adjusted R2R^2 penalizes the inclusion of additional predictors unless they improve the model’s explanatory power significantly.
    • If adding a predictor does not improve the model, Adjusted R2R^2 decreases.
  • Comparison with R- Squared:

    • R2 increases or stays constant as predictors are added, even if those predictors are irrelevant.
    • Adjusted R2 adjusts for the number of predictors, ensuring only meaningful improvements are rewarded.
  • Range:

    • Adjusted R2 is always less than or equal to R2.
    • It can be negative if the model performs worse than a simple mean-based model.
  • Usefulness:

    • Adjusted R2 is particularly useful when comparing models with different numbers of predictors.

(11) Interpretation of Adjusted R-Squared:

(12) Example of Adjusted R-Squared:

(13) Key Takeaways of Adjusted R-Squared:

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