The quarterly sales data (number of copies sold) for a college textbook over the past three years follow. Do not round your intermediate calculations. Click on the datafile logo to reference the data. Quarter Year 1 Year 2 Year 3 1 1,690 1,800 1,850 2 940 900 1,100 3 2,625 2,900 2,930 4 2,500 2,360 2,615 a. Construct a time series plot. 1. 2. 3. time series plot 1 What type of pattern exists in the data