Zerbel Company, a wholesaler of large, custom-built air-conditioning units for commercial buildings, has noticed considerable fluctuation in its shipping expense from month to month, as shown below: Month Units Shipped Total Shipping Expense January 8 $ 3,900 February 9 $ 4,300 March 7 $ 3,500 April 4 $ 1,130 May 5 $ 2,700 June 10 $ 4,700 July 15 $ 2,450 Required: 2-a. Using the high-low method, estimate the cost formula for shipping expense where X is the number of units shipped. 4. What factors, other than the number of units shipped, are likely to affect the company's total shipping expense? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer.) Weight of the units shipped Distance traveled Sales commissions Trade discounts given to repeat customers Express shipping to meet a deadline Zerbel Company, a wholesaler of large, custom-built air-conditioning units for commercial buildings, has noticed considerable fluctuation in its shipping expense from month to month, as shown below: Month Units Shipped Total Shipping Expense January 8 $ 3,900 February 9 $ 4,300 March 7 $ 3,500 April 4 $ 1,130 May 5 $ 2,700 June 10 $ 4,700 July 15 $ 2,450 Required: 2-a. Using the high-low method, estimate the cost formula for shipping expense where X is the number of units shipped. 4. What factors, other than the number of units shipped, are likely to affect the company's total shipping expense? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer.) Weight of the units shipped Distance traveled Sales commissions Trade discounts given to repeat customers Express shipping to meet a deadline