Texas Instruments TI-83 Manual Book page 325

20. Press o to display the
Press | to move the cursor onto the = sign,
and then press Í to deselect
Í to turn off plot 1.
21. Press q
menu. The window variables are
ZOOM
adjusted automatically, and plot 2 is displayed.
This is a scatter plot of the residuals.
Notice the pattern of the residuals: a group of negative residuals, then a
group of positive residuals, and then another group of negative residuals.
The residual pattern indicates a curvature associated with this data set
for which the linear model did not account. The residual plot emphasizes
a downward curvature, so a model that curves down with the data would
be more accurate. Perhaps a function such as square root would fit. Try
a power regression to fit a function of the form y = a ä x
22. Press o to display the
Press ' to clear the linear regression
equation from
plot 1. Press ~ Í to turn off plot 2.
TI-83 Plus Statistics
editor.
Y=
to select
9 9:ZoomStat
editor.
Y=
. Press } Í to turn on
Y
1
. Press }
Y
1
from the
b
.
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