The controller of Oriole Production has collected the following monthly expense data for analyzing the cost behavior of electricity costs. Total Electricity Costs Total Machine Hours January $2,400 250 February 3,010 360 March 3,570 500 April 4,790 690 May 3,150 410 June 4,930 740 July 4,110 630 August 3,880 530 September 5,010 665 October 4,380 630 November 3,320 360 December 5,970 760 What electricity cost does the cost equation estimate for a level of activity of 500 machine hours? Electricity costs $ By what amount does this differ from March's observed cost for 500 machine hours? Amount differ $ What electricity cost does the cost equation estimate for a level of activity of 740 machine hours? Electricity costs $ By what amount does this differ from June's observed cost for 740 machine hours? Amount differ $