Spreadsheet: 539677d1506331666-forecasting-seasonal-forecast-test-25092017
Sheet: LONGCHAIR

Sales | Year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 |  | Total
 | 2015 | 6.25 | 6.25 | 6.25 | 6.25 | 4 | 4 | 4 | 4 | 3 | 11 | 12 | -2 | 11 | 4 | 4 | 18 | 22 | 23 | 56 | 44 | 33 | 34 | 74 | 81 | 58 | 80 | 58 | 70 | 29 | 42 | 61 | 47 | 48 | 54 | 74 | 55 | 53 | 24 | 42 | 40 | 30 | 27 | 18 | 9 | 8 | 11 | 12 | 12 | 8 | 8 | 0 | 0 |  | 1406
 | 2016 | 12 | 2 | 10 | 7 | 7 | 4 | 1 | 20 | 31 | 28 | 16 | 22 | 21 | 67 | 20 | 45 | 21 | 46 | 55 | 21 | 45 | 72 | 112 | 88 | 72 | 59 | 154 | 101 | 127 | 89 | 51 | 86 | 68 | 34 | 50 | 94 | 82 | 95 | 89 | 51 | 64 | 55 | 42 | 21 | 43 | 22 | 10 | 34 | 27 | 25 | 15 | 11 |  | 2381
 | 2017 | 1 | 7 | 1 | 16 | 5 | 2 | 6 | 8 | 9 | 17 | 17 | 27 | 31 | 23 | 44 | 41 | 39 | 23 | 46 | 64 | 113 | 107 | 124 | 118 | 138 | 109 | 82 | 89 | 101 | 234 | 103 | 152 | 88 | 96 | 85 | 126 | 115 | 115 | 77 | 74 | 74 | 68 | 49 | 14 |  |  |  |  |  |  |  |  |  | 2878
 | 2018 | 11.11698161242134 | 8.87530474153056 | 10.11658773191874 | 17.28530247256637 | 9.526914715855153 | 5.999138275992834 | 6.648350340033815 | 19.48406858611058 | 26.37442845049456 | 34.59906570582719 | 28.00449526009341 | 29.45977741321714 | 39.77098225428112 | 59.76210650380148 | 43.53691488605304 | 67.05196224299515 | 53.23538925136052 | 60.13982241473727 | 103.3335346219518 | 85.4827578524628 | 127.4234908355964 | 143.0551352598573 | 209.5916234692098 | 195.3275130171594 | 183.5975076112561 | 171.00765222197 | 204.0444209315572 | 181.6126781254969 | 180.6689332936413 | 258.2278699127638 | 153.0703839224032 | 204.1845255960673 | 147.0673923139698 | 133.4736455644164 | 152.5453182476262 | 201.9499799210769 | 184.7113053019267 | 173.938489701454 | 155.5441756802709 | 124.127882139148 | 127.1376712436967 | 114.1880265749082 | 83.46513335099193 | 33.88954035350665 | 59.26443403169134 | 38.56941702567028 | 25.86083939310528 | 54.38189857780897 | 41.61281856415643 | 39.45678528162085 | 18.03573970254931 | 13.30015646986538 |  | 4854.136268970143
 | Total | 19.25 | 15.25 | 17.25 | 29.25 | 16 | 10 | 11 | 32 | 43 | 56 | 45 | 47 | 63 | 94 | 68 | 104 | 82 | 92 | 157 | 129 | 191 | 213 | 310 | 287 | 268 | 248 | 294 | 260 | 257 | 365 | 215 | 285 | 204 | 184 | 209 | 275 | 250 | 234 | 208 | 165 | 168 | 150 | 109 | 44 | 51 | 33 | 22 | 46 | 35 | 33 | 15 | 11 |  | 6665
 | Weekly Average | 6.416666666666667 | 5.083333333333333 | 5.75 | 9.75 | 5.333333333333333 | 3.333333333333333 | 3.666666666666667 | 10.66666666666667 | 14.33333333333333 | 18.66666666666667 | 15 | 15.66666666666667 | 21 | 31.33333333333333 | 22.66666666666667 | 34.66666666666666 | 27.33333333333333 | 30.66666666666667 | 52.33333333333334 | 43 | 63.66666666666666 | 71 | 103.3333333333333 | 95.66666666666667 | 89.33333333333333 | 82.66666666666667 | 98 | 86.66666666666667 | 85.66666666666667 | 121.6666666666667 | 71.66666666666667 | 95 | 68 | 61.33333333333334 | 69.66666666666667 | 91.66666666666667 | 83.33333333333333 | 78 | 69.33333333333333 | 55 | 56 | 50 | 36.33333333333334 | 14.66666666666667 | 25.5 | 16.5 | 11 | 23 | 17.5 | 16.5 | 7.5 | 5.5 |  | 2221.666666666667
 | Seasonal Indices | 0.002888222055513879 | 0.002288072018004501 | 0.00258814703675919 | 0.004388597149287322 | 0.002400600150037509 | 0.001500375093773444 | 0.001650412603150788 | 0.004801200300075019 | 0.006451612903225807 | 0.008402100525131283 | 0.006751687921980496 | 0.007051762940735184 | 0.009452363090772693 | 0.01410352588147037 | 0.01020255063765942 | 0.01560390097524381 | 0.01230307576894224 | 0.01380345086271568 | 0.02355588897224306 | 0.01935483870967742 | 0.02865716429107277 | 0.03195798949737435 | 0.04651162790697674 | 0.04306076519129783 | 0.04021005251312829 | 0.0372093023255814 | 0.04411102775693924 | 0.03900975243810953 | 0.0385596399099775 | 0.05476369092273069 | 0.03225806451612904 | 0.04276069017254314 | 0.03060765191297825 | 0.02760690172543136 | 0.03135783945986497 | 0.0412603150787697 | 0.03750937734433608 | 0.03510877719429858 | 0.03120780195048762 | 0.02475618904726182 | 0.02520630157539385 | 0.02250562640660165 | 0.01635408852213054 | 0.006601650412603151 | 0.01147786946736684 | 0.007426856714178545 | 0.004951237809452363 | 0.01035258814703676 | 0.007876969242310579 | 0.007426856714178545 | 0.003375843960990248 | 0.002475618904726182
 | Year | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | 2015 | 2163.961038961039 | 2731.557377049181 | 2414.855072463768 | 1424.145299145299 | 1666.25 | 2666 | 2423.636363636364 | 833.125 | 464.9999999999999 | 1309.196428571428 | 1777.333333333333 | -283.6170212765957 | 1163.730158730159 | 283.6170212765957 | 392.0588235294117 | 1153.557692307692 | 1788.170731707317 | 1666.25 | 2377.324840764331 | 2273.333333333333 | 1151.544502617801 | 1063.896713615023 | 1591 | 1881.062717770034 | 1442.425373134328 | 2150 | 1314.863945578231 | 1794.423076923077 | 752.0817120622568 | 766.931506849315 | 1891 | 1099.140350877193 | 1568.235294117647 | 1956.032608695652 | 2359.856459330143 | 1333 | 1412.98 | 683.5897435897435 | 1345.817307692308 | 1615.757575757576 | 1190.178571428571 | 1199.7 | 1100.642201834862 | 1363.295454545455 | 696.9934640522875 | 1481.111111111111 | 2423.636363636364 | 1159.130434782609 | 1015.619047619047 | 1077.171717171717 | 0 | 0
 | 2016 | 4154.805194805194 | 874.0983606557378 | 3863.768115942029 | 1595.042735042735 | 2915.9375 | 2666 | 605.9090909090909 | 4165.625 | 4804.999999999999 | 3332.5 | 2369.777777777778 | 3119.787234042553 | 2221.666666666667 | 4750.585106382979 | 1960.294117647059 | 2883.89423076923 | 1706.890243902439 | 3332.5 | 2334.872611464968 | 1085 | 1570.287958115183 | 2252.957746478873 | 2408 | 2043.623693379791 | 1790.597014925373 | 1585.625 | 3491.190476190476 | 2589.096153846154 | 3293.599221789883 | 1625.164383561644 | 1581 | 2011.19298245614 | 2221.666666666667 | 1231.576086956522 | 1594.497607655502 | 2278.218181818182 | 2186.12 | 2705.876068376068 | 2851.850961538461 | 2060.090909090909 | 2539.047619047619 | 2443.833333333333 | 2568.165137614678 | 3181.022727272727 | 3746.339869281045 | 2962.222222222222 | 2019.69696969697 | 3284.202898550724 | 3427.714285714285 | 3366.161616161616 | 4443.333333333333 | 4443.333333333333
 | 2017 | 346.2337662337662 | 3059.344262295082 | 386.3768115942028 | 3645.811965811965 | 2082.8125 | 1333 | 3635.454545454545 | 1666.25 | 1395 | 2023.303571428571 | 2517.888888888889 | 3828.829787234043 | 3279.603174603174 | 1630.797872340426 | 4312.647058823529 | 2627.548076923077 | 3169.939024390244 | 1666.25 | 1952.8025477707 | 3306.666666666667 | 3943.167539267015 | 3348.145539906103 | 2666 | 2740.313588850174 | 3431.977611940298 | 2929.375 | 1858.945578231292 | 2281.480769230769 | 2619.31906614786 | 4272.904109589041 | 3193 | 3554.666666666667 | 2875.098039215686 | 3477.391304347826 | 2710.645933014354 | 3053.781818181818 | 3065.9 | 3275.534188034188 | 2467.33173076923 | 2989.151515151515 | 2935.773809523809 | 3021.466666666666 | 2996.192660550458 | 2120.681818181818 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
2015 | Period | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | Cumulative Season (X) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | Sales (Y) | 2163.961038961039 | 2731.557377049181 | 2414.855072463768 | 1424.145299145299 | 1666.25 | 2666 | 2423.636363636364 | 833.125 | 464.9999999999999 | 1309.196428571428 | 1777.333333333333 | -283.6170212765957 | 1163.730158730159 | 283.6170212765957 | 392.0588235294117 | 1153.557692307692 | 1788.170731707317 | 1666.25 | 2377.324840764331 | 2273.333333333333 | 1151.544502617801 | 1063.896713615023 | 1591 | 1881.062717770034 | 1442.425373134328 | 2150 | 1314.863945578231 | 1794.423076923077 | 752.0817120622568 | 766.931506849315 | 1891 | 1099.140350877193 | 1568.235294117647 | 1956.032608695652 | 2359.856459330143 | 1333 | 1412.98 | 683.5897435897435 | 1345.817307692308 | 1615.757575757576 | 1190.178571428571 | 1199.7 | 1100.642201834862 | 1363.295454545455 | 696.9934640522875 | 1481.111111111111 | 2423.636363636364 | 1159.130434782609 | 1015.619047619047 | 1077.171717171717 | 0 | 0
 | sum x^2 | 1 | 4 | 9 | 16 | 25 | 36 | 49 | 64 | 81 | 100 | 121 | 144 | 169 | 196 | 225 | 256 | 289 | 324 | 361 | 400 | 441 | 484 | 529 | 576 | 625 | 676 | 729 | 784 | 841 | 900 | 961 | 1024 | 1089 | 1156 | 1225 | 1296 | 1369 | 1444 | 1521 | 1600 | 1681 | 1764 | 1849 | 1936 | 2025 | 2116 | 2209 | 2304 | 2401 | 2500 | 2601 | 2704
 | sum y^2 | 4682727.378141339 | 7461405.7041118 | 5831525.02100399 | 2028189.833077653 | 2776389.0625 | 7107555.999999997 | 5874013.223140495 | 694097.265625 | 216224.9999999999 | 1713995.288584183 | 3158913.777777778 | 80438.61475780894 | 1354267.882338121 | 80438.61475780894 | 153710.1211072664 | 1330695.349482249 | 3197554.565734681 | 2776389.062499999 | 5651673.398515152 | 5168044.444444443 | 1326054.741509279 | 1131876.217240847 | 2531281 | 3538396.948184388 | 2080590.957061706 | 4622499.999999998 | 1728867.195381554 | 3219954.178994083 | 565626.9016184954 | 588183.936198161 | 3575880.999999998 | 1208109.510926439 | 2459361.937716262 | 3826063.566280717 | 5568922.508642199 | 1776888.999999999 | 1996512.4804 | 467294.9375410913 | 1811224.225684171 | 2610672.543617997 | 1416525.031887755 | 1439280.09 | 1211413.256459893 | 1858574.496384297 | 485799.8889316075 | 2193690.12345679 | 5874013.223140495 | 1343583.364839319 | 1031482.049886621 | 1160298.908274666 | 0 | 0
 | sum x*y | 2163.961038961039 | 5463.114754098361 | 7244.565217391304 | 5696.581196581196 | 8331.25 | 15996 | 16965.45454545454 | 6665 | 4184.999999999999 | 13091.96428571428 | 19550.66666666666 | -3403.404255319148 | 15128.49206349206 | 3970.63829787234 | 5880.882352941176 | 18456.92307692308 | 30398.90243902439 | 29992.5 | 45169.17197452229 | 45466.66666666666 | 24182.43455497382 | 23405.72769953051 | 36593 | 45145.50522648083 | 36060.63432835821 | 55899.99999999999 | 35501.32653061225 | 50243.84615384616 | 21810.36964980545 | 23007.94520547945 | 58620.99999999999 | 35172.49122807018 | 51751.76470588235 | 66505.10869565216 | 82594.976076555 | 47987.99999999999 | 52280.26 | 25976.41025641025 | 52486.875 | 64630.30303030302 | 48797.32142857143 | 50387.39999999999 | 47327.61467889907 | 59985 | 31364.70588235294 | 68131.11111111111 | 113910.9090909091 | 55638.26086956521 | 49765.33333333333 | 53858.58585858585 | 0 | 0
2016 | Period | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | Cumulative Season (X) | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104
 | Sales (Y) | 4154.805194805194 | 874.0983606557378 | 3863.768115942029 | 1595.042735042735 | 2915.9375 | 2666 | 605.9090909090909 | 4165.625 | 4804.999999999999 | 3332.5 | 2369.777777777778 | 3119.787234042553 | 2221.666666666667 | 4750.585106382979 | 1960.294117647059 | 2883.89423076923 | 1706.890243902439 | 3332.5 | 2334.872611464968 | 1085 | 1570.287958115183 | 2252.957746478873 | 2408 | 2043.623693379791 | 1790.597014925373 | 1585.625 | 3491.190476190476 | 2589.096153846154 | 3293.599221789883 | 1625.164383561644 | 1581 | 2011.19298245614 | 2221.666666666667 | 1231.576086956522 | 1594.497607655502 | 2278.218181818182 | 2186.12 | 2705.876068376068 | 2851.850961538461 | 2060.090909090909 | 2539.047619047619 | 2443.833333333333 | 2568.165137614678 | 3181.022727272727 | 3746.339869281045 | 2962.222222222222 | 2019.69696969697 | 3284.202898550724 | 3427.714285714285 | 3366.161616161616 | 4443.333333333333 | 4443.333333333333
 | sum x^2 | 2809 | 2916 | 3025 | 3136 | 3249 | 3364 | 3481 | 3600 | 3721 | 3844 | 3969 | 4096 | 4225 | 4356 | 4489 | 4624 | 4761 | 4900 | 5041 | 5184 | 5329 | 5476 | 5625 | 5776 | 5929 | 6084 | 6241 | 6400 | 6561 | 6724 | 6889 | 7056 | 7225 | 7396 | 7569 | 7744 | 7921 | 8100 | 8281 | 8464 | 8649 | 8836 | 9025 | 9216 | 9409 | 9604 | 9801 | 10000 | 10201 | 10404 | 10609 | 10816
 | sum y^2 | 17262406.20678023 | 764047.9441010483 | 14928704.05377021 | 2544161.326612608 | 8502691.50390625 | 7107555.999999997 | 367125.8264462809 | 17352431.640625 | 23088024.99999999 | 11105556.25 | 5615846.716049383 | 9733072.385694886 | 4935802.777777777 | 22568058.85298778 | 3842753.02768166 | 8316845.934264052 | 2913474.304729328 | 11105556.25 | 5451630.111769238 | 1177225 | 2465804.271401552 | 5075818.60741916 | 5798464 | 4176397.800143257 | 3206237.669859657 | 2514206.640624999 | 12188410.94104308 | 6703418.893860946 | 10847795.83377493 | 2641159.273597297 | 2499560.999999999 | 4044897.212680825 | 4935802.777777777 | 1516779.657963137 | 2542422.62081912 | 5190278.083966942 | 4779120.654399999 | 7321765.297410327 | 8133053.906827847 | 4243974.553719008 | 6446762.811791382 | 5972321.36111111 | 6595472.17405942 | 10118905.59142562 | 14035062.41616472 | 8774760.49382716 | 4079175.849403122 | 10785988.67884898 | 11749225.22448979 | 11331044.02611978 | 19743211.11111111 | 19743211.11111111
 | sum x*y | 220204.6753246753 | 47201.31147540984 | 212507.2463768116 | 89322.39316239316 | 166208.4375 | 154628 | 35748.63636363636 | 249937.5 | 293104.9999999999 | 206615 | 149296 | 199666.3829787234 | 144408.3333333333 | 313538.6170212766 | 131339.7058823529 | 196104.8076923077 | 117775.4268292683 | 233275 | 165775.9554140127 | 78120 | 114631.0209424084 | 166718.8732394366 | 180600 | 155315.4006968641 | 137875.9701492537 | 123678.75 | 275804.0476190476 | 207127.6923076923 | 266781.5369649805 | 133263.4794520548 | 131223 | 168940.2105263158 | 188841.6666666667 | 105915.5434782608 | 138721.2918660287 | 200483.2 | 194564.68 | 243528.8461538461 | 259518.4375 | 189528.3636363636 | 236131.4285714286 | 229720.3333333333 | 243975.6880733944 | 305378.1818181818 | 363394.9673202614 | 290297.7777777778 | 199950 | 328420.2898550724 | 346199.1428571428 | 343348.4848484848 | 457663.3333333333 | 462106.6666666666
2017 | Period | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | Cumulative Season (X) | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 | 115 | 116 | 117 | 118 | 119 | 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 | 128 | 129 | 130 | 131 | 132 | 133 | 134 | 135 | 136 | 137 | 138 | 139 | 140 | 141 | 142 | 143 | 144 | 145 | 146 | 147 | 148 | 149 | 150 | 151 | 152 | 153 | 154 | 155 | 156
 | Sales (Y) | 346.2337662337662 | 3059.344262295082 | 386.3768115942028 | 3645.811965811965 | 2082.8125 | 1333 | 3635.454545454545 | 1666.25 | 1395 | 2023.303571428571 | 2517.888888888889 | 3828.829787234043 | 3279.603174603174 | 1630.797872340426 | 4312.647058823529 | 2627.548076923077 | 3169.939024390244 | 1666.25 | 1952.8025477707 | 3306.666666666667 | 3943.167539267015 | 3348.145539906103 | 2666 | 2740.313588850174 | 3431.977611940298 | 2929.375 | 1858.945578231292 | 2281.480769230769 | 2619.31906614786 | 4272.904109589041 | 3193 | 3554.666666666667 | 2875.098039215686 | 3477.391304347826 | 2710.645933014354 | 3053.781818181818 | 3065.9 | 3275.534188034188 | 2467.33173076923 | 2989.151515151515 | 2935.773809523809 | 3021.466666666666 | 2996.192660550458 | 2120.681818181818 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
 | sum x^2 | 11025 | 11236 | 11449 | 11664 | 11881 | 12100 | 12321 | 12544 | 12769 | 12996 | 13225 | 13456 | 13689 | 13924 | 14161 | 14400 | 14641 | 14884 | 15129 | 15376 | 15625 | 15876 | 16129 | 16384 | 16641 | 16900 | 17161 | 17424 | 17689 | 17956 | 18225 | 18496 | 18769 | 19044 | 19321 | 19600 | 19881 | 20164 | 20449 | 20736 | 21025 | 21316 | 21609 | 21904 | 22201 | 22500 | 22801 | 23104 | 23409 | 23716 | 24025 | 24336
 | sum y^2 | 119877.8208804182 | 9359587.315237839 | 149287.0405377021 | 13291944.89005771 | 4338107.91015625 | 1776888.999999999 | 13216529.75206612 | 2776389.0625 | 1946024.999999999 | 4093757.342155612 | 6339764.456790122 | 14659937.53961068 | 10755796.98286722 | 2659501.700430059 | 18598924.65397923 | 6904008.896542159 | 10048513.41835217 | 2776389.062499999 | 3813437.790579739 | 10934044.44444444 | 15548570.24272909 | 11210078.55639313 | 7107556 | 7509318.56523692 | 11778470.32885943 | 8581237.890624998 | 3455678.662825674 | 5205154.500369822 | 6860832.370285696 | 18257709.52974291 | 10195249 | 12635655.11111111 | 8266188.735101881 | 12092250.28355387 | 7347601.374167257 | 9325583.39305785 | 9399742.81 | 10729124.21698079 | 6087725.869660687 | 8935026.780532598 | 8618767.860685939 | 9129260.817777775 | 8977170.459136434 | 4497291.373966942 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
 | sum x*y | 36354.54545454545 | 324290.4918032787 | 41342.3188405797 | 393747.6923076923 | 227026.5625 | 146630 | 403535.4545454545 | 186620 | 157635 | 230656.6071428571 | 289557.2222222222 | 444144.2553191489 | 383713.5714285714 | 192434.1489361702 | 513204.9999999999 | 315305.7692307692 | 383562.6219512195 | 203282.5 | 240194.7133757962 | 410026.6666666666 | 492895.9424083769 | 421866.3380281689 | 338582 | 350760.1393728222 | 442725.1119402985 | 380818.7499999999 | 243521.8707482993 | 301155.4615384615 | 348369.4357976653 | 572569.1506849314 | 431054.9999999999 | 483434.6666666666 | 393888.4313725489 | 479879.9999999999 | 376779.7846889952 | 427529.4545454545 | 432291.9 | 465125.8547008546 | 352828.4374999999 | 430437.8181818182 | 425687.2023809523 | 441134.1333333332 | 440440.3211009174 | 313860.9090909091 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0
Total |  | Total
 | Cumulative Season (X) | 12246 |  | b | a
 | Sales (Y) | 328806.6666666666 |  | 29.87024962581102 | -840.5547784321614
 | sum x^2 | 1277666 |  | Sales=b(Season)+a
 | sum y^2 | 895180614.3002957
 | sum x*y | 27870768.54173122
2018 | Period | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 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 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52
 | Cumulative Season (X) | 157 | 158 | 159 | 160 | 161 | 162 | 163 | 164 | 165 | 166 | 167 | 168 | 169 | 170 | 171 | 172 | 173 | 174 | 175 | 176 | 177 | 178 | 179 | 180 | 181 | 182 | 183 | 184 | 185 | 186 | 187 | 188 | 189 | 190 | 191 | 192 | 193 | 194 | 195 | 196 | 197 | 198 | 199 | 200 | 201 | 202 | 203 | 204 | 205 | 206 | 207 | 208
 | Sales (Y) | 3849.074412820168 | 3878.944662445979 | 3908.81491207179 | 3938.685161697601 | 3968.555411323412 | 3998.425660949223 | 4028.295910575034 | 4058.166160200845 | 4088.036409826656 | 4117.906659452467 | 4147.776909078279 | 4177.64715870409 | 4207.5174083299 | 4237.387657955711 | 4267.257907581522 | 4297.128157207333 | 4326.998406833144 | 4356.868656458955 | 4386.738906084766 | 4416.609155710577 | 4446.479405336388 | 4476.3496549622 | 4506.219904588011 | 4536.090154213822 | 4565.960403839633 | 4595.830653465443 | 4625.700903091254 | 4655.571152717065 | 4685.441402342876 | 4715.311651968687 | 4745.181901594498 | 4775.052151220309 | 4804.922400846121 | 4834.792650471932 | 4864.662900097743 | 4894.533149723554 | 4924.403399349365 | 4954.273648975176 | 4984.143898600987 | 5014.014148226797 | 5043.884397852608 | 5073.754647478419 | 5103.624897104231 | 5133.495146730042 | 5163.365396355853 | 5193.235645981664 | 5223.105895607475 | 5252.976145233286 | 5282.846394859097 | 5312.716644484908 | 5342.586894110719 | 5372.45714373653
 | Seasonal Indices | 0.002888222055513879 | 0.002288072018004501 | 0.00258814703675919 | 0.004388597149287322 | 0.002400600150037509 | 0.001500375093773444 | 0.001650412603150788 | 0.004801200300075019 | 0.006451612903225807 | 0.008402100525131283 | 0.006751687921980496 | 0.007051762940735184 | 0.009452363090772693 | 0.01410352588147037 | 0.01020255063765942 | 0.01560390097524381 | 0.01230307576894224 | 0.01380345086271568 | 0.02355588897224306 | 0.01935483870967742 | 0.02865716429107277 | 0.03195798949737435 | 0.04651162790697674 | 0.04306076519129783 | 0.04021005251312829 | 0.0372093023255814 | 0.04411102775693924 | 0.03900975243810953 | 0.0385596399099775 | 0.05476369092273069 | 0.03225806451612904 | 0.04276069017254314 | 0.03060765191297825 | 0.02760690172543136 | 0.03135783945986497 | 0.0412603150787697 | 0.03750937734433608 | 0.03510877719429858 | 0.03120780195048762 | 0.02475618904726182 | 0.02520630157539385 | 0.02250562640660165 | 0.01635408852213054 | 0.006601650412603151 | 0.01147786946736684 | 0.007426856714178545 | 0.004951237809452363 | 0.01035258814703676 | 0.007876969242310579 | 0.007426856714178545 | 0.003375843960990248 | 0.002475618904726182
 | Forecast Sales | 11.11698161242134 | 8.87530474153056 | 10.11658773191874 | 17.28530247256637 | 9.526914715855153 | 5.999138275992834 | 6.648350340033815 | 19.48406858611058 | 26.37442845049456 | 34.59906570582719 | 28.00449526009341 | 29.45977741321714 | 39.77098225428112 | 59.76210650380148 | 43.53691488605304 | 67.05196224299515 | 53.23538925136052 | 60.13982241473727 | 103.3335346219518 | 85.4827578524628 | 127.4234908355964 | 143.0551352598573 | 209.5916234692098 | 195.3275130171594 | 183.5975076112561 | 171.00765222197 | 204.0444209315572 | 181.6126781254969 | 180.6689332936413 | 258.2278699127638 | 153.0703839224032 | 204.1845255960673 | 147.0673923139698 | 133.4736455644164 | 152.5453182476262 | 201.9499799210769 | 184.7113053019267 | 173.938489701454 | 155.5441756802709 | 124.127882139148 | 127.1376712436967 | 114.1880265749082 | 83.46513335099193 | 33.88954035350665 | 59.26443403169134 | 38.56941702567028 | 25.86083939310528 | 54.38189857780897 | 41.61281856415643 | 39.45678528162085 | 18.03573970254931 | 13.30015646986538