Gibson Company manufactures a wide range of electrical products at several different plant locations. Due to fluctuations, its Lanford plant has been experiencing difficulties in estimating the level of monthly overhead.
Management needs more accurate estimates to plan its operational and financial needs. A trade association publication indicates that for similar plants, overhead tends to vary with direct labor hours. Based on this information, one member of the accounting staff proposes that the overhead cost behavior pattern be determined to calculate the overhead cost in relation to budgeted direct labor hours. Another member of the accounting staff suggests that a good starting place for determining the cost behavior pattern of the overhead cost would be an analysis of historical data to provide a basis for estimating future overhead costs.
Direct labor hours and the respective factory overhead costs for the past three years are as follows:

Required:
(1) Compute the amount of fixed factory overhead and the variable cost rate, using the method of least squares. Round fixed factory overhead to the nearest dollar and the variable cost rate to the nearest cent.
(2) Compute the coefficient of correlation, r, and the coefficient of determination, r2, for factory overhead costs and direct labor hours. (Round to four decimal places.)
(3) Compute the standard error of the estimate. (Round to the nearest dollar.)
(4) Compute the 95% confidence interval for factory overhead costs at the 2,200-direct-labor-hour level of activity. (Assume that the sample size is sufficiently large that the normal probability distribution can be assumed and that the correction factor for small samples can be omitted. Round to the nearest dollar.)

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20А 20B 20C Direct Factory Direct Factory Direct Factory Labor Overhead Labor Overhead Labor Overhead Hours Costs Hours Costs Hours Costs Month January.. 2,000 $8,500 2,100 $8,700 2,000 $8,600 February 2,400 9,900 2,300 9,300 2,300 9,300 2,200 8,950 2,200 9,300 2,300 9,400 2,300 9,000 2,200 8,700 2,200 8,700 2,000 8,150 2,000 8,000 2,000 8,100 1,900 7,550 1,800 7,650 ,800 7,600 1,400 7050 1,200 6,750 1,000 6,450 00 7, 1,200 6,900 1,700 7,500 1,700 7,250 1,600 7,150 1,900 7,800 1,800 7,500 1,900 7,600 May June July August 1,300 7,000 100 200 6,900 30 7,100 1,800 7,500 1,500 7,000 1,500 7,350 October.. 1,500 7,100 December.