The data:

The following data report total, monthly U.S. book-store sales in millions of dollars from January 2016 to March 2019. (Go to https://www.census.gov/retail/index.html#mrts, find "Monthly Retail Trade Report," then select "Time Series/Trend Charts" to find the data for the total U.S. bookstore sales.) Year Month 2016 2017 2018 2019 January $1, 608 $1, 526 $1, 411 $1, 284 February 867 831 849 806 March 859 847 874 825 April 849 869 850 May 918 921 927 June 853 844 867 July 827 809 841 August 1, 664 1, 514 1, 504 September 1, 204 1, 137 1, 126 October 855 829 881 November 882 843 908 December 1, 396 1, 297 1, 399e. What is. the average monthly trend in bookstore sales? {Negative amounts should be indicated by a minus sign. Round your answer to 4 decimal placesJ fv'l. What are the monthly indexes? (Round your answers to 4 decimal places} f-2. When are book sales the highest? When are book sales the highestf-3. When are book sales the lowest? When are book sales the lowest g. Predict book sales for the next 9 months. (Round your answers to 4 decimal places.) Year Month Forecast Sales 2019 April 2019 May 2019 June 2019 July 2019 August 2019 September 2019 October 2019 November 2019 Decemberd. Evaluate a seasonally adjusted trend forecasting model What Is the MAD? (Round your answers to 4 decimal places.} Month $ Sales Period Trend Index Forecast Absolute Number [Millions] Error 1.608 1 867 859 849 918 853 827 1.664 1.204 9 10 855 10 11 BB 11 12 1.396 12 1.526 13 831 14 847 15 869 16 921 17 844 309 19 1,514 20 1,137 21 829 22 843 23 1.297 24 1,411 25 B49 26 874 27 850 28 927 29 867 30 B41 31 1.504 32 1.126 33 10 BB1 34 11 908 35 12 1.399 36 1 284 37 BD6 38 825 39 MAD=