Salesperson
the General Manager of a Chain of Furniture Stores

Essay

Salesperson
The general manager of a chain of furniture stores believes that experience is the most important factor in determining the level of success of a salesperson.To examine this belief she records last month's sales (in $1,000s)and the years of experience of 10 randomly selected salespeople.These data are listed below.
$$\begin{array} { | c | c | c | } \hline \text { Ealesperson } & \text { Years of Experience } & \text { Eales } \\\hline 1 & 0 & 7 \\\hline 2 & 2 & 9 \\\hline 3 & 10 & 20 \\\hline 4 & 3 & 15 \\\hline 5 & 8 & 18 \\\hline 0 & 5 & 14 \\\hline 7 & 12& 20 \\\hline 8 &7 & 17 \\\hline 9 &20 & 30 \\\hline 10 & 15& 25 \\\hline\end{array}$$
-If the regression equation is $\hat { y } = 8.63 + 1.0817 x$ ,plot the residuals against the predicted values of y.Does the variance appear to be constant?