Question 13.77

13.77 U.S. air carrier traffic.

Consider monthly total number of passenger miles on U.S. domestic flights from the previous exercise.

airtrav

  1. Use the moving-average approach to compute seasonal ratios and report their values.
  2. Produce and plot the seasonally adjusted series. What are your impressions of this plot?
  3. Fit a trend model and report the -value of the trend coefficient. Is there enough evidence of the presence of trend?
  4. Given your conclusion of part (c), forecast total number of passenger miles to be flown in June 2014.

13.77

(a) 0.888, 0.833, 1.050, 0.995, 1.038, 1.098, 1.152, 1.108, 0.931, 0.995, 0.937, 0.966. (b) The seasonally adjusted series increases over time and is quite stable. (c) . The trend term is significant, . (d) For June 2014: 54,037,215.