seasonality "Problem", please submit the Excel Formula as well, Thank you. (There is no way to upload excel file).

A B C E F G H ) K L M N O P R S 1 Period 2 3 4 5 year 1 2 2 3 > 4 5 season 1 1 1 - 1 1. D sales 1 2 3 50 70 60 80 We have a data set for 9 years and there are four season throughout a year. By using linear regression method, creat seasonal forecast for year 10 (periods 37, 38, 39, and 40). 4 1 55 6 6 7 8 9 10 2 2 2 2 7 . 8 2 3 4 75 65 85 9 10 11 12 13 14 1 15 16 10 17 18 3 3 3 2 3 3 4 4 * 4 4 1 2 3 3 4 1 2 3 60 80 20 70 an 90 65 85 75 4 5 5 4 1 2 95 70 90 80 3 5 5 100 75 6 6 11 12 13 14 15 13 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 19 20 21 22 23 24 25 26 4 1 2 3 3 4 1 2 6 6 7 7. 7 7 7 8 8 3 27 28 95 85 105 80 100 100 90 110 85 105 95 115 90 29 30 31 32 33 o 8 9 4 1 2 3 3 4 1 2 3 4 1 9 34 35 9 110 100 120 36 . 37 20 38 9 9 10 10 10 2 39 40 3 4 10 49 A B C E F G H ) K L M N O P R S 1 Period 2 3 4 5 year 1 2 2 3 > 4 5 season 1 1 1 - 1 1. D sales 1 2 3 50 70 60 80 We have a data set for 9 years and there are four season throughout a year. By using linear regression method, creat seasonal forecast for year 10 (periods 37, 38, 39, and 40). 4 1 55 6 6 7 8 9 10 2 2 2 2 7 . 8 2 3 4 75 65 85 9 10 11 12 13 14 1 15 16 10 17 18 3 3 3 2 3 3 4 4 * 4 4 1 2 3 3 4 1 2 3 60 80 20 70 an 90 65 85 75 4 5 5 4 1 2 95 70 90 80 3 5 5 100 75 6 6 11 12 13 14 15 13 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 19 20 21 22 23 24 25 26 4 1 2 3 3 4 1 2 6 6 7 7. 7 7 7 8 8 3 27 28 95 85 105 80 100 100 90 110 85 105 95 115 90 29 30 31 32 33 o 8 9 4 1 2 3 3 4 1 2 3 4 1 9 34 35 9 110 100 120 36 . 37 20 38 9 9 10 10 10 2 39 40 3 4 10 49