How to Calculate R-squared
What is R-squared?
R² (coefficient of determination) measures the proportion of variance in the dependent variable that is predictable from the independent variable(s). R²=0.80 means 80% of variation in Y is explained by the model.
Step-by-Step Guide
- 1R² = 1 − SS_residual / SS_total
- 2SS_total = Σ(yi − ȳ)²
- 3SS_residual = Σ(yi − ŷi)²
- 4For simple linear regression: R² = r²
Worked Examples
Input
SS_total=100 · SS_residual=30
Result
R² = 0.70 — model explains 70% of variance
Reasonable for many real-world applications
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