The controller of Chittenango Chain Company believes that the identification of the variable and fixed components of the firm's costs will enable the firm to make better planning and control decisions. Among the costs the controller is concerned about is the behavior of indirect-materials cost. She believes there is a correlation between machine hours and the amount of indirect materials used. A member of the controller's staff has suggested that least-squares regression be used to determine the cost behavior of indirect materials. The regression equation shown below was developed from 40 pairs of observations. S = $175 + $4H where S = Total monthly cost of indirect materials H Machine hours per month 4. The high and low activity levels during the past four years, as measured by machine hours, occurred during April and August, respectively. Data concerning machine hours and indirect-material usage follow. Machine hours Indirect supplies: Beginning inventory Ending inventory Purchases April August 1,600 1,000 $1,900 $1,600 1,650 3,600 6,500 6,800 Determine the cost of indirect materials used during April and August. Cost of indirect materials used April August