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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, using either the fitted trend model or a judgment forecast? Why is it best to ignore earlier years in this data set?
U.S. General Aviation Shipments 1966-03
YearPlanesYearPlanesYearPlanesYear
196615,587197615,4511986 1,4951996
196713,484197716,9041987 1,0851997
196813,556197817,8111988 1,1431998
196912,407197917,0481989 1,5351999
1970 7,277198011,8771990 1,1342000
1971 7,3461981 9,4571991 1,0212001
1972 9,7741982 4,2661992 8562002
197313,6461983 2,6911993 8702003
197414,1661984 2,4311994 881
197514,0561985 2,0291995 1,028________________________________________YearPlanes
19961,053 2001 2,538
19971,482 2002 2,169
19982,115 2003 2,090
1999 2,421
2000 2,714
U.S. General Aviation Shipments 1966-03
YearPlanesYearPlanesYearPlanesYear
196615,587197615,4511986 1,4951996
196713,484197716,9041987 1,0851997
196813,556197817,8111988 1,1431998
196912,407197917,0481989 1,5351999
1970 7,277198011,8771990 1,1342000
1971 7,3461981 9,4571991 1,0212001
1972 9,7741982 4,2661992 8562002
197313,6461983 2,6911993 8702003
197414,1661984 2,4311994 881
197514,0561985 2,0291995 1,028________________________________________YearPlanes
19961,053 2001 2,538
19971,482 2002 2,169
19982,115 2003 2,090
1999 2,421
2000 2,714