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Graphing Calculator Notes Graphing a Residual plot using the TI-84:Place the data into L1 and L2.Create the Linear Regression Stat-CALC-#4Lin Reg.IMPORTANT: In order for the calculator to compare your data to your Linear Regression, the calculator needs to be made to create the linear regression, by YOU! Place the residuals in L3 (see other residual notes if you don’t remember how).Line of best to the nearest ten thousandth as found by the graphing calculator:y = 0.9736x + 8.9961 (your Y1 screen should have the full unrounded slope and y-intercept).360372116483600xyResidualsFrom TI-8410201.26731519-4.601018303.478020290.53072531-2.338025351.6624To have the calculator graph a Residual Plot: After you have placed the x-values and y-values in the L1 and L2 and RESIDS in L3.Go to 2nd Y= , STAT PLOT, and make sure it is on. Next hit enter and scroll to the Y LIST. When Y LIST is highlighted and L2 is flashing change L2 to L3. Now select ZOOM #9 for the residual plot to appear.41189918388600360411618415000(Alternate for those that are comfortable with the above: The other way to get the residual plot for the given data in L1 and L2 is to get the Linear Regression into Y= and not worry about pulling the residuals into L3.Go to 2nd Y= , STAT PLOT, hit enter and scroll to the Y LIST. When Y LIST is highlighted and L2 is flashing replace it with the RESIDS by going right to 2nd STAT for LIST and selecting #7 RESIDS. Now select ZOOM #9 for the residual plot to appear.For either method once you have the graph on the screen you can use:the TRACE key and arrows to see the RESIDUALS for each x-value in your L1.The PREDICTED y-values based on the least-squares line in the Y= can be found in the table. By keying 2nd GRAPH you can pull up the table for the linear regression found by your inputs.The table of x & y values:37720210033003578237101073These y-values are not the ones you keyed into your L2. Those were the actual data values. These are the predicted values that the calculator uses to determine the residuals.These y-values are not the ones you keyed into your L2. Those were the actual data values. These are the predicted values that the calculator uses to determine the residuals.18008604635500When the Residual Plot is on the screen of the TI-84 you can also find the predicted y-values.Hit 2nd TRACE for CALC. You want When you hit ENTER it brings you backVALUE, which is highlighted. to the residual plot with x = flashing.364680567310037719059690You can now place any value of x in andThe value will match what was in the Y1 tablefind the corresponding predicted y-value.Here is when x = 10Here is when x = 25 (Note: these must be x-values that are in L1 The table will give you all values) 35350451263650152401263650Try other x-values to find predicted y-values and compare them to the table of X1 and Y1 values.Does this residual plot imply that the data has a linear relationship? Explain.Try these: Input the data into L1 and L2. Get the linear regression into the Y= . Graph the residual plot.Residuals are shown here to the nearest thousandth.1) Compare your residuals & graph to these:213360137160xyResiduals530.571104-0.8571591.714207-2.71425130.85730150.42900xyResiduals530.571104-0.8571591.714207-2.71425130.85730150.42933625774770902) Compare your residuals & graph to these:33625772902670136297217230xyResiduals100505-2.857904601.286804155.42970360-0.42960305-6.286502652.85700xyResiduals100505-2.857904601.286804155.42970360-0.42960305-6.286502652.857 ................
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