Using the yearly amount of solar power generated by utilities (in millions of kWh) in the United States from 2002 through 2018 data for Problem 16.16 on page 572 (stored in Solar Power),
a. Fit a third-order autoregressive model to the amount of solar power installed and test for the significance of the third-order autoregressive parameter. (Use a = 0.05.)
b. If necessary, fit a second-order autoregressive model to the amount of solar power installed and test for the significance of the second-order autoregressive parameter. (Use a = 0.05.)
c. If necessary, fit a first-order autoregressive model to the amount of solar power installed and test for the significance of the first-order autoregressive parameter. (Use a = 0.05.)
d. Forecast the yearly amount of solar power generated by utilities (in millions of kWh) in the United States in 2019.

Problem 16.16

The data shown in the following table and stored in Solar Power represent the yearly a mount of solar power generated by utilities (in millions of kWh) in the United States from 2002 through 2018:

Solar Power Solar Power Generated Generated Year (millions of kWh) Year (millions of kWh) 2002 555 2010 1,212 2003 534 2011 1.818 2004 575 2012 4,327 2005 551 2013 9.253 2006 508 2014 18,321 2007 612 2015 26,473 2008 864 2016 36,754 2009 892 2017 52,958 2018 66,604