(a) Plot the data on U.S. general aviation shipments.
(b) Describe the pattern and discuss possible causes.
(c) Would a fitted trend be helpful? Explain.
(d) Make a similar graph for 1992-2003 only. Would a fitted trend be helpful in making a prediction for 2004?
(e) Fit a trend model of your choice to the 1992-2003 data.
(f) Make a forecast for 2004, using either the fitted trend model or a judgment forecast. Why is it best to ignore earlier years in this data set?
|
U.S Manufactured general aviation shipments( 1966 - 2003)
|
|
Year
|
planes
|
year
|
planes
|
year
|
planes
|
year
|
planes
|
|
1966
|
15,587
|
1976
|
15,451
|
1986
|
1,495
|
1996
|
1,053
|
|
1967
|
13,484
|
1977
|
16,904
|
1987
|
1,085
|
1997
|
1,482
|
|
1968
|
13,556
|
1978
|
17,811
|
1988
|
1,143
|
1998
|
2,115
|
|
1969
|
12,407
|
1979
|
17,048
|
1989
|
1,535
|
1999
|
2,421
|
|
1970
|
7,277
|
1980
|
11,877
|
1990
|
1,134
|
2000
|
2,714
|
|
1971
|
7,346
|
1981
|
9,457
|
1991
|
1,021
|
2001
|
2,538
|
|
1972
|
9,774
|
1982
|
4,266
|
1992
|
856
|
2002
|
2,169
|
|
1973
|
13,646
|
1983
|
2,691
|
1993
|
870
|
2003
|
2,090
|
|
1974
|
14,166
|
1984
|
2,431
|
1994
|
881
|
|
|