| 1. Enter lists | |
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Clear all lists |
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Set up editor |
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Get ready to edit lists; position cursor at top of list L1 |
| Enter x values, pressing
after each one |
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Position cursor at top of L2 list |
| Enter y values, pressing after each one |
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Quit |
| 2. Graph the data | |
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Turn Plot 1 On |
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Highlight first type of graph Xlist is L1 |
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Quit |
| 3. Do the linear regression; the equation will be of the form y(x) = ax + b | |
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Go to STAT CALC and do LinReg(ax+b) |
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Values of a, b, r, and r2 appear on screen; a = slope; b = y intercept |
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| Note: If r and its value do not appear on screen, it must be turned on: | |
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Use the CATALOG |
| Press as many times as needed to position the
pointer at DiagnosticOn |
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From now on, until it is turned off, the values of r and r2 will appear on screen for all linear regressions |
| Start at the top of Step 3 again. | |
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| 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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Regression line is graphed with data points |
| 5. Use the regression line to make predictions | |
| Method 1: If the x value where the prediction is to be made is in the current graphing window, |
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And then enter the x value where the prediction is to be made |
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Y value is the predicted value |
| If the x value is not in the current graphing window, the window can be reset to include that x value. It is not necessary to have the y value in the window. Then use the process above. | |
| Method 2: | |
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Use TblSet |
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Set Indpnt: to Ask and Depend: to Auto Quit And then enter the x value in the X column; the corresponding value in the Y1 column is the predicted value |
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| 6. When regression is completed, turn scatter plots off | |
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