16. Use the Box-Jenkins methodology to model and forecast the monthly sales of the Cavanaugh Company given in Table P-14. (Hint: Consider a log transformation before modeling these data.)

TABLE P-14 Period Observation Period Observation Period Observation 1 101 31 16 61 79 2 84 32 17 62 53 3 54 33 21 63 40 4 39 34 28 64 27 5 26 35 30 65 31 6 40 36 51 66 56 7 99 37 62 67 78 8 148 38 57 68 114 9 147 39 46 69 140 10 134 40 40 70 112 11 106 41 32 71 82 12 83 42 23 72 80 13 76 43 20 73 70 14 63 44 18 74 55 15 57 45 24 75 37 16 37 46 33 76 23 17 32 47 52 77 20 18 22 48 66 78 39 19 20 49 78 79 71 20 23 50 83 80 110 21 30 51 87 81 112 22 50 52 64 82 93 23 61 53 44 83 75 24 59 54 24 84 60 25 64 55 29 85 63 26 58 56 73 86 46 27 44 57 138 87 32 28 26 58 154 88 23 29 24 59 119 89 53 30 18 60 102 90 90