今天老师又分发新问题了~~~~要了我的命~~~怎么算都算不出~~~~
Sebastian works in a financial division in a retail food company. Under his supervision he has 14 medium-sized stores that he has to look after. He has to make sure sales and targeted sales are achieved as predicted. He is given a new store in Umbria, Lake District to forecast the sale for period 17, based on 16 months historical data. Because he has no experience in dealing with the particular retail shop, from his opinion the best way to predict its sales is using two-parameter exponential smoothing which he considers α = 0.4 and γ = 0.1 are the best parameters in predicting the sales. In the data that he analyzed, parameter T and b in the period 8 equal to 10.06579468 and 1.140456645 respectively. From his analyzing he finds out F16 is more than F8 by 14.00874664 (in thousands) and the ratio of parameter b for period 16 to parameter b for period 15 is equal to 1.076117008. The actual sales (in thousands) for period 8 and 16 are 10 and 27 respectively. Find forecast sale in period 17 based on the given information above.