Please help me answer the questions (a, b. c, d) for no. 24.

24. The following data shows the average interest rate (%) for a 30-year fixed-rate mortgage over a ten-year period (FreddieMac website, July 30, 2016). Year Interest Rate (%) 2006 6.41 2007 6:34 2008 6.03 DATA file 2009 5.04 2010 4.69 Mortgage 2011 4.45 2012 3.66 2013 3.98 2014 4.17 2015 3.85 a. Construct a time series plot. Do you think a linear trend or a quadratic trend will pro- vide a better fit for this time series? Why? b. Develop the linear trend equation for this time series. Using this linear trend equation, forecast the average interest rate for 2016. c. Develop the quadratic trend equation for this time series. Using this quadratic trend equation, forecast the average interest rate for 2016. d. Compare your answers to parts (b) and (c). Which model would you recommend? Why? 25. Quarterly revenue ($ millions) for Twitter for the first quarter of 2012 through the first quarter of 2014 are shown below (adexchange.com, April 2015)