The potentially deadly 2009 Swine Flu outbreak was due to a new flu strain of subtype H1N1 not previously reported in pigs. When the World Health Organization declared a pandemic, the virus continued to spread in the United States, causing illness along with regular seasonal influenza viruses. Consider the following 2009 weekly data on total Swine Flu cases in the United States, reported by the Centers for Disease Control and Prevention (CDC).
a. Plot the series. Estimate the linear and the quadratic trend models. Use their adjusted R2to choose the preferred model.
b. Given the preferred model, make a forecast for the number of Swine Flu cases in the U.S. for week 27.