Business Forecasting 6th Edition by Holton Wilson, Barry Keating, John Solutions

تمرين 2

Using The Gap sales data for 1985Q1 through 2005Q4, calculate the four-period centered moving average of The Gap sales (call it GAPCMA). Then, using a time index that goes from 1 for 1985Q1 through 84 for 2005Q4, estimate the trend of GAPCMA (call this trend GAPCMAT and extend it through the entire 1985Q1-2007Q1 period). Plot The Gap sales, GAPCMA, and GAPCMAT on the same graph for the period from 1985Q1 through 2005Q4.