Stafford Company makes sailboats. During the first six months of 2002, Stafford had the following production expenses: Month Units Produced Production Expenses January 60 $ 12,000 February 50 11,000 March 80 15,000 April 70 13,400 May 16,000 June 40 10,000 90 REQUIRED: Using the high-low method, estimate the variable and fixed cost elements of the production cost and write out the cost formula