Example of Using Automatic Recalc

This example uses the Companies.jmp sample data table, which contains financial data for 32 companies from the pharmaceutical and computer industries.

Select Help > Sample Data Library and open Companies.jmp.

Select Analyze > Fit Y by X.

Select Sales ($M) and click Y, Response.

Select # Employ and click X, Factor.

Click OK.

Figure 6.149 Initial Scatterplot

The initial scatterplot shows that one company has significantly more employees and sales than the other companies. You decide that this company is an outlier, and you want to exclude that point. Before you exclude the point, turn on Automatic Recalc so that your scatterplot is updated automatically when you make the change.

Turn on Automatic Recalc by selecting Redo > Automatic Recalc from the red triangle menu.

Click on the outlier to select it.

Select Rows > Exclude/Unexclude. The point is excluded from the analysis and the scatterplot is automatically updated.

Figure 6.150 Updated Scatterplot

If you fit a regression line to the data, the point in the lower right corner is an outlier, and influences the slope of the line. If you then exclude the outlier with Automatic Recalc turned on, you can see the slope of the line change.

Fit a regression line by selecting Fit Line from the red triangle menu. Figure 6.151 shows the regression line and analysis results added to the report window.

Figure 6.151 Regression Line and Analysis Results

10.

Click on the outlier to select it.

11.

Select Rows > Exclude/Unexclude. The regression line and analysis results are automatically updated, reflecting the exclusion of the point.

Tip: When you exclude a point, the analyses are recalculated without the data point, but the data point is not hidden in the scatterplot. To also hide the point in the scatterplot, select the point, and then select Rows > Hide and Exclude.

Figure 6.152 Updated Regression Line and Analysis Results