A hospital records the number of floral deliveries its patients receive each day. For a two-week period, the records show
15, 27, 26, 24, 18, 21, 26, 19, 15, 28, 25, 26, 17, 23
Use a three-period moving average and report the forecast error for period 5 using 2 numbers after the decimal point. Use absolute value. Show all of your work.