Demand and Forecasting

RUNNING HEADER: DEMAND AND FORECASTING 1
Demand and Forecasting
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Demand and Forecasting 2
Chapter 5
1. Plot the raw data on arrivals for each transportation mode against time, all on the
same graph. Which mode is growing the fastest? Which the slowest?
Raw
YEAR CRUISE FERRY
HIGHWA
Y AIR
1983 48,066 25,288 72,384 3,500
1984 54,907 25,196 79,215 3,750
1985 77,623 31,522 89,542 4,000
1986 100,695 30,981 91,908 4,250
1987 119,279 30,905 70,993 4,953
1988 115,505 31,481 74,614 5,957
1989 112,692 29,997 63,789 7,233
1990 136,512 33,234 63,237 4,799
1991 141,284 33,630 64,610 4,853
1992 145,973 37,216 79,946 7,947
1993 192,549 33,650 80,709 10,092
1994 204,387 34,270 81,172 10,000
1995 256,788 33,961 87,977 17,000
1996 299,651 35,760 86,536 20,721
1997 438,305 27,659 91,849 11,466
1998 494,961 31,324 100,784 20,679
1999 525,507 31,467 92,291 15,963

Demand and Forecasting 3
1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
-
100,000
200,000
300,000
400,000
500,000
600,000
Chart Title
CRUISE FERRY HIGHWAY AIR
From the figure above, it can be seen that the mode of arrival that is the fastest growing is
through the cruise. On the other hand, the mode of arrival which is the slowest cannot be pointed
out since the ferry, highway and air mode of arrivals can be seen to be constant.
2. Plot the logarithm of arrivals for each transportation mode against time, all on the
same graph. Which now appears to be growing the fastest?
Logarithm of arrivals
YEAR
CRUIS
E
FERR
Y
HIGHWA
Y
AI
R
1983 4.68 4.40 4.86
3.5
4
1984 4.74 4.40 4.90
3.5
7
1985 4.89 4.50 4.95
3.6
0
1986 5.00 4.49 4.96
3.6
3
1987 5.08 4.49 4.85
3.6
9
1988 5.06 4.50 4.87
3.7
8
1989 5.05 4.48 4.80
3.8
6

Demand and Forecasting 4
1990 5.14 4.52 4.80
3.6
8
1991 5.15 4.53 4.81
3.6
9
1992 5.16 4.57 4.90
3.9
0
1993 5.28 4.53 4.91
4.0
0
1994 5.31 4.53 4.91
4.0
0
1995 5.41 4.53 4.94
4.2
3
1996 5.48 4.55 4.94
4.3
2
1997 5.64 4.44 4.96
4.0
6
1998 5.69 4.50 5.00
4.3
2
1999 5.72 4.50 4.97
4.2
0
1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
Chart Title
CRUISE FERRY HIGHWAY AIR
From the figure above, it is evident that the cruise and air mode of arrival is the fastest growing.
On the other hand, the ferry and highway modes of arrival can be seen to be constant.
3. Logarithms are especially useful for comparing series with two divergent scales
since 10 percent growth always looks the same, regardless of the starting level.