A statistical program is recommended.

A company provides maintenance service for water$-$filtration systems throughout southern Florida. Customers contact the company with requests for maintenance service on their water$-$filtration systems. To estimate the service time and the service cost, the company's managers want to predict the repair time necessary for each maintenance request. Hence, repair time in hours is the dependent variable. Repair time is believed to be related to three factors, the number of months since the last maintenance service, the type of repair problem $($mechanical or electrical$),$ and the repairperson who performed the service. Data for a sample of $10$ service calls are reported in the table below.