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-score of -1.50. What was the z-score for the cost of that service call?