Texas Instruments TI-83-Plus - ³ Tipé 8: Finding the Best Line of Fit for a Set of Data

TIp 8: Finding the Best Line of Fit for a Set of Data
Topics in Algebra 1 © 2001 Texas Instruments
³
TIp 8-1
³
TIp
é
8: Finding the Best Line of Fit for a Set of Data
Both the TI
-
83 Plus and the TI
-
73 have regression commands that automatically find the closest
equation to your statistical plot data. The
LinReg(ax+b)
command finds the closest linear
equation
y=ax+b
and displays the values for
a
(slope) and
b
(y-intercept) on the Home screen.
You can save this equation in the Y= editor so that you can graph the regression equation and the
statistical plot data at the same time, and then compare the two.
Calculator Keys Used in This
³
TIp
é
•
TI
-
83 Plus: … ~ (
CALC
menu)
LinReg(ax+b)
•
TI
-
73:
- v !
(
CALC
menu)
LinReg(ax+b)
³
TIp
é
Highlights
This
³
TIp shows you how to use
LinReg(ax+b)
on the Home screen to find the linear regression
of two list names,
XList
(
L
1
) and
YList
(
L
2
)
. You will use the same list values that you used to
define the statistical plot.
Note
: For more information about statistical plots, see
³
TIp 7:
Creating a Statistical Plot
.
In the
³
Try-It! example, you will find a linear regression following these main steps.
1. Select
LinReg(ax+b)
from the …
CALC
menu.
2. Enter the two list names that define the statistical plot.
3. Save the equation in the Y= editor.
4. Graph the statistical plot and the linear regression.
Note:
The examples in the next section assume that the calculator has been reset to the default settings as described in
³
TIp 1:
Resetting Your Calculator.
Statistical plot data points
Linear Regression line based
on statistical plot data