Problem 3 The Custom Products Company needs to predict the labor cost in producing made-to-order mugs. The following production information is available: Year Mugs Produced Labor-Hours Labor Cost 2009 2,300 1,700 $10,800 2010 3,200 1,950 $14,000 2011 2,200 1,600 $15,100 2012 4,200 2,300 $21,400 2013 3,000 1,900 $19,400 2014 2,600 1,750 $19,800 a. Select the appropriate independent variable for estimating labor cost. Explain the reason for your selection. b. Develop an equation for labor costs using the high-low method of cost estimation, and predict total costs for an annual usage of 2,500 labor hours.