Texas TI-86 用户手册

19APPS.DOC   TI-86, Chap 19, US English   Bob Fedorisko   Revised: 02/13/01 2:41 PM   Printed: 02/13/01 3:05 PM   Page 249 of 18

19APPS.DOC   TI-86, Chap 19, US English   Bob Fedorisko   Revised: 02/13/01 2:41 PM   Printed: 02/13/01 3:05 PM   Page 249 of 18

�   Select 

 from the 

GRAPH

 menu to display the stat plot and

trace cursor on the graph screen.

�   Trace the stat plot to approximate the value of 

 at

. With this statistical data, the closest to 

that you can trace to is 

 (on the y-axis).

�   Select 

 from the 

MATH

 menu to display the

interpolate

àextrapolate editor. To interpolate 

 at

, enter the nearest pairs:

�   Enter 

 and solve for 

.

쐅 On the home screen, select 

 from the 

STAT

 

CALC

 menu to fit

the linear regression model equation to the data stored to 

and 

. Write down the value of the result variable 

.

쐈 Fit the logarithmic (

), exponential (

), and power (

) regressions to the data, writing

down the value of 

 for each regression. Compare the 

 values of each regression to

determine which model fits the data most accurately (the 

 value closest to 

).

쐉 Execute the most accurate regression again, and then select

 from the 

STAT

 menu. To forecast 

 at 

,

enter 

 and solve for 

.

Compare this answer with the answer returned in step 9.

The 

s and 

s in parentheses

specify the 7th and 8th
elements of 

 and

.

To enter each regression
after 

, press  

-

 

¢

and edit as needed.