Scatter Chart Selection and High-Low Points Method. Merciful Arms Hospital installed a new body scanner last year. In trying to estimate the expected cost of operating and maintaining the scanner in the current year, the hospital's controller has been reviewing cost and use data for each of the past four quarters, as shown below: Number al Number of Hours Total Quarter Patients Used Cost 1st 100 75 $10,750 2nd 350 200 12,500 3rd 400 550 15.000 4th 250 300 13,000