College tuition has risen at a pace faster than inflation for more than two decades, according to an article in USA Today. The following data indicate the average college tuition (in 2003 dollars) for public colleges:

a. Produce a time-series plot of these data. Indicate the time-series components that exist in the data.
b. Provide a forecast for the average tuition for public colleges in the academic year 2013 through 2014.
c. Provide an interval of plausible values for the average tuition change after five academic periods have gone by. Use a confidence level of 0.90.