The following information is available regarding the total manufacturing overhead of Bursa Mfg. Co. for a recent four-month period: Machine-Hours Manufacturing Overhead Jan. 6,000 $ 310,000 Feb. 3,200 224,000 Mar. 4,900 263,800 Apr. 2,600 190,000 a-1 Use the high-low method to determine the variable element of manufacturing overhead costs per machine-hour.  Manufacturing overhead cost $ per machine hour a-2 Use the high-low method to determine the fixed element of monthly overhead cost.  Fixed element of manufacturing overhead $ b. Bursa expects machine-hours in May to equal 5,300. Use the cost relationships determined in part a to forecast May's manufacturing overhead costs. (Round your intermediate calculations to 2 decimal places. Omit the "tiny_mce_markerquot; sign in your response.) Estimated manufacturing overhead $ c. Suppose Bursa had used the cost relationships determined in part a to estimate the total manufacturing overhead expected for the months of February and March. By what amounts would Bursa have over- or underestimated these costs? (Negative amounts should be indicated by a minus sign. Amount over estimated February $ March $.