1. We observed that adding a point on a scatterplot did not change ???? or the line of best fit. Use the formulas for correlation and linear regression, show that adding a point at (????̅, ????̅) does not affect ????. (Note: this is not as simple as it might first seem! While the extra ????−????̅ and ????−????̅ terms are 0, we are also changing the denominator for every other point by changing ????!)

2. Like number 1: show that adding a point at (????̅, ????̅) does not affect the least-squares regression line in any way. This is ????̂ =????0 +????1???? equation.