A data set contains points (1,3),(2,5),(3,7),(4,9)(1,3),(2,5),(3,7),(4,9)(1,3),(2,5),(3,7),(4,9) and (10,k)(10,k)(10,k). Without the fifth point, all points lie on y=2x+1y=2x+1y=2x+1.
Find the value of k k\,k that places the fifth point on the same line.
If k=−20k=-20k=−20, describe the likely effect of the fifth point on the fitted regression line.
State one check to make before deciding whether to remove it.