R-square-Adj-R-Square

Measures to Find accuracy :

Classification	Regression
Confusion Matrix, Accuracy Score, True Positive Rate, F1 Score, Precision , Recall	R-square & Adjusted R square

Formulas for Rsquare & Adjusted R square

1.R-square

• R^2 = 1 - SSres / SStot

• SSres = Sum of Residual or error

• sum(yi - yi^)2 (Square because we have negative value)

• 1.Here we found the best fit line

• SStot = Sum of average total = sum(Yi - Y^ avg)2

• 1.Here we found the average of best fit line then find the distance and then do summation.

Difference between R2 adj AND R2

1. Every time you add a independent variable to a model, the R-square increases, even if the independent variable is insignificant. It never declines. Whereas Adjusted R- squared increases only when independent variable is significant and affects dependept variable.
2. Adjusted r-squared value always be less than or equal to r-squared value.