Book Sales a Publishing Company Pays Its Sales Staff $\$ 600$

Essay

Book sales A publishing company pays its sales staff $\$ 600$ a week plus a commission of $\$ 0.50$ per book sold. For example, a salesman who sold 440 books earned $600 + 0.50 ( 440 ) =$ $\$ 820$ .
a. The table shows summary statistics for the number of books the large sales staff sold last week. Fill in the table to show the statistics for the pay these people earned.
$\begin{array}{|l|c|l|}\hline \text { Statistic } & \text { Books Sold } & \text { \$ Earned } \\\hline \text { Mean } & 640 & \\\hline \text { St. dev. } & 360 & \\\hline \text { IQR } & 450 & \\\hline \text { Maximum } & 1420 & \\\hline\end{array}$

b. The newest employee had a pretty good week. Among all the salespeople her pay corresponded to a $z$ -score of $+ 1.80$ . What was the $z$ -score of the number of books she sold?