House Calls a Local Plumber Makes House Calls B This Past Month, the Time the Plumber Spent on $30

House calls A local plumber makes house calls. She charges $30 to come out to the house
and $40 per hour for her services. For example, a 4-hour service call costs $30 + $40(4) =
$190.
a. The table shows summary statistics for the past month. Fill in the table to find out the
cost of the service calls. $$\begin{array} { | l | c | l | } \hline \text { Statistic } & \text { Hours of Service Call } & \text { Cost of Service Call } \\\hline \text { Mean } & 4.5 & \\\hline \text { Median } & 3.5 & \\\hline \text { SD } & 1.2 & \\\hline \text { IQR } & 2.0 & \\\hline \text { Minimum } & 0.5 & \\\hline\end{array}$$
b. This past month, the time the plumber spent on one service call corresponded to a $z \text {-score of } - 1.50 \text {. }$
0. What was the z-score for the cost of that service call?