The service center at a large automobile dealership is trying to boost revenue by providing 'no appointment necessary' oil changes to any type of vehicle that stops by the service center. The number of 'no appointment necessary' oil changes that the service center completed over the past four weeks is given in the Excel spreadsheet. Last week, the service manager's forecast for the number of no appointment necessary oil changes was 58. Please answer the following three questions, based on this information. a. What was the error in the service manager's forecast last week? b. Suppose the service manager decided to use a 2-week moving average. What would be the service manager's forecast for this week?