3 We are using Winter’s method and monthly data to forecast the GDP. (All numbers are in billions of dollars.)

At the end of January 2005, Lt  600 and Tt  5. We are given the following seasonalities: January, 0.80; February, 0.85; December, 1.2. During February 2005, the GDP is at a level of 630. At the end of February what is the forecast for the December 2005 level of the GDP? Use a  b 

g  0.5.