Machine hours and electricity costs for AMK Industries for the past year were as follows: Month Machine Hours Electricity Costs January 2000 18900 February 2400 21500 March 1400 14000 April 2600 23500 Required: Using the high-low method, develop an estimate of variable electricity costs per machine hour. Using the high-low method, develop an estimate of fixed electricity costs per month. Estimate electricity costs for a month in which 1,500 machine hours are worked.