Hi.. R Program is shown ARIMA output as below then SARIMA equation is be (1 - 0.991B^{12})z_t + 43.557 = (1+0.37B)(1-0,915B^{12})a_t But I try to calculate it by manual . It look like it 's big different from R sofeware, I am not sure this equation is correct or not . PLS supoort me to confirm it Arima Model ( 0,0,1)(1,0,1) No Transformation Constant >> 43.557 , t = 10.09 MA >> -0.37 , t = -4.806,Lag 1 AR,Seasonal>> 0.991 , t = 48.098,Lag 1 MR,Seasonal>> 0.915 , t = 9.487 ,Lag 1 Forcasting Output 42.06226126 37.74729393 37.59225405 32.2574074 42.15854259 47.98722125 59.33493345 44.09434137 37.79761267 37.64391567 32.35527663 42.17065344 47.94884716 59.19827147 44.08968535 37.84749558 37.69512982 32.45229818 42.18265938 47.91080545 59.06279319 44.08506965 Input data 19.56 46.84 51.58 28 33.92 26.11 37.59 66.16 69.77 74.29 53.4 45.61 80.13 65.4 60.32 79.35 73.15 59.27 46.15 45.7 47.05 48.97 43.55 58.32 60.07 27.29 1.45 14.14 55.85 68.3 58.42 48.85 37.65 45.2 34.42 54.75 40.19 35.77 19.12 28.38 31.39 22.52 37.05 50.8 61.7 27.3 35.27 43.2 42.37 45.67 72.32 48.4 24.65 21.01 35.19 24.66 38.3 51.46 57.92 49.71 24.51 45.61 37.05 25.18 38.62 48.83 42.87 41.02 27.14 30.31 52.5 65.73 59.46 47.36 33.02 47.71 21.53 28.74 56.61 62.86 47.36 41.97 8.52 40.59 56.87 35.27 62.85 39.97 53.47 41.92 49.82 54.94 50.78 70.71 36.8 27.19 36.8 26.56 38.81 58.38 58.93 36.29 27.82 37.65 10.8 40.05 48.11 80.41 61.55 33.05 35.85 38.04 35.6 26.41 56.12 34.03 29.47 37.42 25.36 42.38 46.82 78.54 38.74 55.02 38.45 23.81 43.7 36.04 88.13 69.47 43.86 22.02 18.04 45.75 52.18 50.85 38.49 38.8 46.16 36.38 32.16 53.32 54.64 49.56 35.31 40.81 30.71 33.25 35.04 50.21 [[alternative HTML version deleted]]