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 was $75 and it was $100 for the second. Compute z values for each and comment on your findings.© BrainMass Inc. brainmass.com October 24, 2018, 6:48 pm ad1c9bdddf
The first z-value is negative because the value of x = 75 is less than the mean ...
This solution provides the appropriate formulas and a step by step methodology, with the calculations formatted, in the attached Word document. An interpretation of the z-values is also given.
Ford Super Duty F-750
Fast Service Truck Lines uses the Ford Super Duty F-750 exclusively. Management made
a study of the maintenance costs and determined the number of miles traveled during
the year followed the normal distribution. The mean of the distribution was 60,000 miles
and the standard deviation 2,000 miles.
a. What percent of the Ford Super Duty F-750s logged 65,200 miles or more?
b. What percent of the trucks logged more than 57,060 but less than 58,280 miles?
c. What percent of the Fords traveled 62,000 miles or less during the year?
d. Is it reasonable to conclude that any of the trucks were driven more than 70,000 miles?