A simple linear regression model was fitted to two variables: Y, the response variable and X, the explanatory variable. A scatter plot of Y versus X as well as the residual plot after fitting the least squares regression line to the data are given below. 3.5 2.5 2 1.5 1 05 2 4 6 8 10 X 1.5 1 0.5 Residuals 10 -0.5 -1 1.5 X