Question

Four pairs of data yield r=0.942 and the regression equation y-hat=3x. Also, y-bar=12.75. What is the best predicted value for x=4.3?

I know that the answer is 12.5, but how do you know to use the y-bar value instead of plugging the x value into the equation?

Answer 1

Nevermind, I figured it out!! :)

Answer 2

Well, I have the same question and can't figure it out how do you know when to use which one?