Regression and R-squared

Regression(회귀) line

Drawing a line that represents a pattern in data. Regression line predicts the change in y when x increases by one unit.

b0: intercept

b1: slope.

y hat: predicted value of y

 

R-squared

Literally means the square of r. (r: correlation variable)

Has value between 0 and 1.

Meaning: measure of how close each data point fits to the regression line. Tells us how well the regression line predicts actual values. Also means the percentage of variation in y that is accounted for by its regression on x.

*Meaning of r: measurement of the linear relationship between two quantitative variables with respect to direction and strength