Given the following table of U.S. population:
[Extracted from the Census Bureau WWW site.]
find and graph the exponential model which best approximates the data.
Using the TI-85 graphing calculator:
[Press here to see animation again!]
- Press the STAT key and then pick  EDIT  by pressing the F2 key.
- You can change the names for the list of values which you will be entering
but it is not necessary. Press the ENTER key twice if
do not change the names.
- To clear out previous data, pick  CLRxy  by pressing the F5 key.
- At the prompt  x1= , type in the first year as the first
x-value: 1790 and press the ENTER key.
- At the prompt  y1= , type in the first population value as
first y-value: 3929 and press the ENTER key.
- Keep repeating this to enter all eight pairs of numbers. After you have
entered the tenth pair, press the EXIT key.
- Pick  CALC  by pressing the F1 key.
- Press the ENTER key twice and you will be given the
opportunity to choose a number of options including  EXPR  ;
choose this option by pressing the F2 key since we
want the exponential model.
- You will see the following screen:
This indicates that the equation of the exponential model is:
y = (4.50164040853 10- 20) (1.02995397837)x
- Press the EXIT key followed by the DRAW key.
- If some previous graph appears on the screen then
- pick  CLDRW by pressing the F5 key.
- If the previous graph still appears then press the GRAPH key and choose  y(x)=  by pressing the
- Press F4 key several times until no
function appears on the screen.
- Proceed with changing the bounds of the viewing screen as outlined in
the next item.
- Most probably you will need to change to the bounds of the viewing screen
to see all of the data points. To do this,
- Press the GRAPH key and then choose  RANGE  by pressing the
- Enter the following data:
- You will then need to press the EXIT key
followed by the STAT and DRAW keys to return where you were.
- Pick  SCAT by pressing the F2 key
to see the collection of data points:
- Pick  DRREG by pressing the F4 key
to draw the graph of the exponential model: