Functions Defined by Data
Part 1: First
Class Postage Rates
The following table lists
first class postage rates (in cents), with each rate paired with the year
in which it took effect. The time frame for this data is more than a century.
(Source of data: Associated Press, 7/2/97.)
| Year |
Postage
(cents) |
|
|
Year |
Postage
(cents) |
| 1885 |
2 |
|
|
1976 |
13 |
| 1918 |
3 |
|
|
1978 |
15 |
| 1919 |
2 |
|
|
1981 |
18 |
| 1932 |
3 |
|
|
1982 |
20 |
| 1958 |
4 |
|
|
1985 |
22 |
| 1963 |
5 |
|
|
1988 |
25 |
| 1968 |
6 |
|
|
1991 |
29 |
| 1971 |
8 |
|
|
1995 |
32 |
| 1974 |
10 |
|
|
1999 |
33 |
- The worksheet you downloaded
to start your computer algebra system contains a command for defining a
list of data points that match the data in the table above. Enter the command
to construct the list of data points.
- Next you will find a command
for making a scatter plot of the data. Enter that command, and experiment
with any plot options you find in the worksheet.
- In your worksheet, write
a brief description of what you learn from the graph about postage costs
in the United States. One or two complete sentences should suffice.
modules at math.duke.edu
