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 patterns that vary over the hours in the day. On July 15, 16, and 17, the following levels of nitrogen dioxide were observed for the 12 hours from 6:00 A.M. to 6:00 P.M. July 15: 25 28 35 50 60 60 40 35 30 25 25 20 July 16: 28 30 35 48 60 65 50 40 35 25 20 20 July 17: 35 42 45 70 72 75 60 45 40 25 25 25 Choose the correct time series plot. (i) (ii) (iii) (iv) Plot (iv) What type of pattern exists in the data? Slight Upward Trend Pattern with Seasonality Use a multiple linear regression model with dummy variables as follows to develop an equation to account for seasonal effects in the data: Note that when the values of the 11 dummy variables are equal to 0, the observation corresponds to the 5:00 P.M. to 6:00 P.M. hour. If required, round your answers to three decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300) Value = + HOUR1 + HOUR2 + HOUR3 + HOUR4 + HOUR5 + HOUR6 + HOUR7 + HOUR8 + HOUR9 + HOUR10 + HOUR11 + t Using the equation developed in part (b), compute estimates of the levels of nitrogen dioxide for July 18. If required, round your answers to three decimal places. Period Forecast 6:00 a.m. − 7:00 a.m. 7:00 a.m. − 8:00 a.m. 8:00 a.m. − 9:00 a.m. 9:00 a.m. − 10:00 a.m. 10:00 a.m. − 11:00 a.m. 11:00 a.m. − noon noon − 1:00 p.m. 1:00 p.m. − 2:00 p.m. 2:00 p.m. − 3:00 p.m. 3:00 p.m. − 4:00 p.m. 4:00 p.m. − 5:00 p.m. 5:00 p.m. − 6:00 p.m.