Air   pollution control specialists in southern California monitor the amount of   ozone, carbon dioxide, and nitrogen dioxide in the air on an hourly basis.   The hourly time series data exhibit seasonality, with the levels of   pollutants showing similar patterns over the hours in the day. On July 15,16   and 17, the observed level of nitrogen dioxide in a city’s downtown area for   the 12 hours from 6:00 A.M. to 6:00 P.M. were as follows.   15-Jul   16-Jul   17-Jul      a. Identify the hourly   seasonal indexes for the 12 hourly daily readings.      b. Based on the seasonal   indexes in part (a), the trend equation developed for the deseasonalized data   T=32.983 + 0.03922t. Using   only the trend equation, develop forecast for the 12 hours for July 18.      c. Using the seasonal indexes   from part (a) to adjust the trend forecasts in part (b).