Chapter 6, Problem 6.7SE

Prepare and analyze a scatterplot (Learning Objective 3)

Montrose Oil and Lube is a car care center specializing in ten-minute oil changes. Montrose Oil and Lube has two service bays, which limits its capacity to 4,000 oil changes per month. The following information was collected over the past six months:

Month	Number of Oil Changes	Operating Expenses
January	3,200	$36,400
February	2,600	$31,900
March	2,800	$32,850
April	2,700	$32,500
May	3,600	$37,000
June	2,900	$33,700

1. 1. Prepare a scatterplot graphing the volume of oil changes (x-axis) against the company’s monthly operating expenses (y-axis). Graph by hand or use Excel
2. 2. How strong a relationship does there appear to be between the company’s operating expenses and the number of oil changes performed each month? Explain. Do there appear to be any outliers in the data? Explain.
3. 3. Based on the graph, do the company’s operating costs appear to be fixed, variable, or mixed? Explain how you can tell.
4. 4. Would you feel comfortable using this information to project operating costs for a volume of 3,800 oil changes per month? Explain.