I'm not sure how to resolve this:
A recent article in the Cincinnati Enquirer reported that the mean labor cost to repair a heat pump is $90 with a standard deviation of $22. Monte's Plumbing and Heating Service completed repairs on two heat pumps this morning. The labor cost for the first is $75 and it was $100 for the second. Compute Z values for each and comment on your findings.
This solution provides calculations and explanations for computing Z values.