Appliance Center sells a variety of electronic equipment and home appliances. For the last 4 years, 2013 through 2016, the following quarterly sales (in $ millions) were reported.

Quarter
Year I II III IV
2013 5.33 4.22 6.68 6.64
2014 4.66 3.68 5.8 6.61
2015 4.39 3.71 5.5 6.64
2016 5.61 4.28 6.45 5.3

a. Determine a typical seasonal index (adjusted) for each of the four quarters. (Round your answers to 4 decimal places.)
b. Use the seasonal indexes you computed to determine the deseasonalized sales. Determine the linear trend equation based on the quarterly data for the 4 years.