Explanation
The statement in Option A is actually false and represents the correct answer to this "EXCEPT" question.
Understanding Adjusted R²
Adjusted R² is a modified version of R² that accounts for the number of predictors in the model. The correct formula for adjusted R² is:
Adjusted R2=1−(1−R2)×n−k−1n−1
Where:
- R2 is the coefficient of determination
- n is the sample size
- k is the number of independent variables
Why Option A is Incorrect
The formula given in Option A:
Adjusted R2=1−TSSSSR×n−k−1n−1
Is incorrect because:
- TSSSSR represents 1−R2 (not R² itself)
- The correct adjustment should be applied to 1−R2, not to TSSSSR directly
Key Properties of Adjusted R²
- Penalizes for adding irrelevant variables
- Can be negative when the model performs worse than the mean
- Always less than or equal to R²
- Increases only if the new variable improves the model more than expected by chance
Since this is an "EXCEPT" question, we're looking for the false statement, which is Option A.