Texas Instruments TI-92 Getting Started page 25

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Graphing Technology Guide: TI-92
Figure 5.68: Plot1 menu
Figure 5.69: Scatter plot
When you no longer want to see the scatter plot, press APPS 6[Data/Matrix Editor] 1 [Current] F2[Plot Setup],
highlight Plot 1 and use F4[ ] to deselect plot 1. The TI-92 still retains all the data you entered.
5.5.3 Regression Line: The TI-92 calculates slope and y-intercept for the line that best fits all the data. After the data
points have been entered, while still in the Data/Matrix Editor, press F5[Calc]. For the Calculation Type, choose
5[LinReg] and set the x variable to c1 and the y variable to c2. In order to have the TI-92 graph the regression
equation, set Store RegEQ to as y1(x) as shown in Figure 5.70. Press ENTER and the TI-92 will calculate a linear
regression model with the slope named a and the y-intercept named b (Figure 5.71). The correlation coefficient
measures the goodness of fit of the linear regression with the data. The closer the absolute value of the correlation
coefficient is to 1, the better the fit; the closer the absolute value of the correlation coefficient is to 0, the worse the
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fit. The TI-92 displays both the correlation coefficient and the coefficient of determination (R ).
Figure 5.70: Linear regression: Calculate dialog box
Figure 5.71: Linear regression model
Press ENTER to accept the regression equation and close the STAT VARS screen. To see both the data points and
the regression line (Figure 5.72), go to the Plot Setup screen and select Plot1, then press GRAPH to display the
graph.
Figure 5.72: Linear regression line
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