Jamie Johnson auto repair shop maintenance cost mixed and varies most directly with labor hours worked. The following data have been gathers recent operations:

Hours of activities……Maintenance Costs

January 480 4200

February 320 3000

March 400 3600

April 300 5800

May 500 4300

June 310 2960

July 320 3030

August 520 4470

September 490 4260

October 470 4050

November 350 3300

December 340 3160

Total 4800 43200

**Instruction**

**A. **Use the High-Low method to estimate a cost formula for maintenance.

**B.** Use least squares regression to estimate a cost formula for maintenance.

**C. **Use your answer on (A) to find the total cost of Maintenance for the next three month of the following year is the number of hours used as follows:

January the following year= 420 hours

February the following year=510 hours

March the following year= 360 hours

**D. **Use your answer on (B) to find the total cost of Maintenance for the next three month of the following year is the number of hours used as follows:

January the following year= 420 hours

February the following year=510 hours

March the following year= 360 hours