South Shore Construction builds permanent docks and seawalls along the southern shoreof Long Island, New York. Although the firm has been in business only five years, revenuehas increased from...

South Shore Construction builds permanent docks and seawalls along the southern shoreof Long Island, New York. Although the firm has been in business only five years, revenuehas increased from $308,000 in the first year of operation to $1,084,000 in the most recentyear. The following data show the quarterly sales revenue in thousands of dollars.Quarter Year 1 Year 2 Year 3 Year 4 Year 51 20 37 75 92 1762 100 136 155 202 2823 175 245 326 384 4454 13 26 48 82 181a. Construct a time series plot. What type of pattern exists in the data?b. Use the following dummy variables to develop an estimated regression equation toaccount for seasonal effects in the data. Qtr1  1 if Quarter 1, 0 otherwise; Qtr2  1if Quarter 2, 0 otherwise; Qtr3  1 if Quarter 3, 0 otherwise. Based only on the seasonaleffects in the data, compute estimates of quarterly sales for year 6.c. Let Period  1 to refer to the observation in quarter 1 of year 1; Period = 2 to refer tothe observation in quarter 2 of year 1; . . . and Period  20 to refer to the observationin quarter 4 of year 5. Using the dummy variables defined in part (b) and Period, developan estimated regression equation to account for seasonal effects and any lineartrend in the time series. Based upon the seasonal effects in the data and linear trend,compute estimates of quarterly sales for year 6.