Refer to the sales data for the years 2013 through 2016 shown in Exercise 16-20 and provide a seasonally adjusted forecast using the linear trend model for each quarter of the year 2017. Also use the seasonal index values computed in Exercise 16-21 to provide seasonally adjusted forecasts for the four quarters of 2017.

Data from exercise 16.20

        2013 ................................................................................. 2015
1st quarter 152 ........................................................... 1st quarter 217
2nd quarter 162 ........................................................ 2nd quarter 209
3rd quarter 157 .......................................................... 3rd quarter 202
4th quarter 167 ........................................................... 4th quarter 221

        2014 ................................................................................ 2016
1st quarter 182 ............................................................ 1st quarter 236
2nd quarter 192 ......................................................... 2nd quarter 242
3rd quarter 191 ........................................................... 3rd quarter 231
4th quarter 197 ........................................................... 4th quarter 224