Texas Instruments TI-82 Getting Started page 24

Figure I.69: Plot1 menu
To draw the scatter plot in a window adjusted automatically to include all the data you entered, press
ZOOM 9 [ZoomStat].
When you no longer want to see the scatter plot, press
ENTER. The TI-82 still retains all the data you entered.
I.5.3 Regression Line: The TI-82 calculates the slope and
The TI-82 can calculate regression lines in two equivalent forms. After the data points have been entered,
press STAT 5 [LinReg(ax + b)] ENTER to calculate a linear regression model with the slope named a
intercept named b (Figure I.71). By pressing STAT
and the y-
produces a linear regression model with the roles of a and b reversed. The number r (between
called the correlation coefficient and measures how well the linear regression equation fits the data. The
closer r is to 1, the better the fit; the closer
Turn Plot1 on again, if it is not currently displayed. Graph the regression line
inactivating any existing functions, moving to a free line or clearing one, then pressing VARS 5 [Statistics...]
7 [RegEQ] GRAPH. See how well this line fits with your data points (Figure I.72).
Figure I.71: Linear regression model
I.5.4 Other Regression Models: After data points have been entered, you can choose from seven different
regression models. They are all located in the CALC sub-menu of the STAT menu.
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Figure I.70: Scatter plot
STAT
2nd 1 , move the cursor to OFF, and press
PLOT
y- intercept for the line that best fits all the data.
9 [LinReg(a + bx)] ENTER, the TI-82
r is to 0, the worse the fit.
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Figure I.72: Linear regression line
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1 and 1) is
b by pressing Y=,
y ax
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TI-82 Graphics Calculator