MATH121
Linear Regression on TI-81
1. Enter lists | |
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Clear all statistical lists |
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Get ready to enter data |
Enter pairs of x and y values, pressing ![]() |
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Quit |
2. Graph the data | |
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Clear all equations Y1 thru Y4 |
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Use the STAT DRAW menu to graph the data points in a scatter graph |
3. Do the linear regression; the equation will be of the form y(x) = a + bx | |
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On the STAT menu, go to LinReg to do the linear regression. |
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Values of a, b, and r appear on screen b = slope; a = y intercept |
4. Paste the linear regression equation into Y1 and graph it | |
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Regression equation is pasted into Y1 |
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Now the STAT DRAW menu will sketch a graph of the regression line and the scatter plot |
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5. Use the regression line to make predictions | |
If the prediction is to be made at X = 5, use the keystrokes below. Replace the 5' with the number of your choice. | |
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The number of your choice is now stored in the variable X |
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The regression equation stored in Y1 is evaluated at the value stored in X |