Quarterly GDP values. The gross domestic product (GDP) is the total US output of goods and services valued at market prices. The beginning of quarter GDP values (in billions of current dollars) for the period 2015–2019 are given in the accompanying table. Using weights w = .5 and n = .5, calculate Holt forecasts for the four quarters of 2020. Year Quarter GDP Year Quarter GDP 2015 1 17,984.18 2017 3 19,611.70 2015 2 18,219.41 2017 4 19,918.91 2015 3 18,344.71 2018 1 20,163.16 2015 4 18,350.83 2018 2 20,510.18 2016 1 18,424.28 2018 3 20,749.75 2016 2 18,637.25 2018 4 20,897.80 2016 3 18,806.74 2019 1 21,098.83 2016 4 18,991.88 2019 2 21,340.27 2017 1 19,190.43 2019 3 21,525.82 2017 2 19,356.65 2019 4 21,747.39 Source: US Department of Commerce, Bureau of Economic Analysis.