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A residual plot is a graph that displays the difference between the observed values and the predicted values of a data set. To create a residual plot on a TI-84 calculator, you need to enter your data into a list, set up a scatter plot of your data, and then create a linear regression. Once the linear regression is created, you can access the residual plot by selecting “Resid” from the Y= menu. This residual plot will help you determine the quality of the linear regression model.
A residual plot is used to assess whether or not the in a regression analysis are normally distributed and whether or not they exhibit .
This tutorial provides a step-by-step example of how to create a residual plot for the following dataset on a TI-84 calculator:
Step 1: Enter the Data
First, we will enter the data values.
Press Stat, then press EDIT. Then enter the x-values of the dataset in column L1 and the y-values in column L2:
Step 2: Perform Linear Regression
Next, we will fit a linear regression model to the dataset.
Press Stat, then scroll over to CALC. Then scroll down to LinReg(ax+b) and press ENTER.
Press ENTER once again to perform linear regression:
The fitted regression model is: y = 7.397 + 1.389x
Step 3: Create the Residual Plot
Next, press 2nd and then press Y=. In the new screen that appears, press ENTER on the first plot option.
The term “RESID” will then appear next to Ylist:
Lastly, press ZOOM and then scroll down to ZoomStat and press ENTER.
The residual plot will appear:
The x-axis displays the x values from the dataset and the y-axis displays the residuals from the regression model.
To see the actual values of the residuals, press 2nd and then press STAT. Then press “7” to choose the residuals:
Press ENTER once more to display the residuals.
Scroll to the right to see the values for each of the residuals.