Regression - Diagnostic - Plot - Scale-Location

Create a plot of the square root of the absolute standardized residuals by fitted values

A chart of the square root of the absolute standardized residuals by fitted values. Also known as a Spread-Location or S-L plot.

Example

The following example shows the output from running this QScript on a Regression - Poisson Regression output.

Acknowledgements

Uses the plot.lm or plot.glm functions from the stats R package.

References

Belsley, D. A., Kuh, E. and Welsch, R. E. (1980). Regression Diagnostics. New York, NY: Wiley.

Code

includeWeb("QScript R Output Functions");

main();

function main() {

    // The following 2 variables contain information specific to this diagnostic.
    var required_class = "Regression";
    var output_name_suffix = "scale.location";
    
    var item = checkSelectedItemClass(required_class);
    if (item == null)
        return false;
    var r_name = stringToRName(item.referenceName);

    // The following lines contain the R code to run
    var expression = "plot(" + r_name + ", which = 3)"

    return createROutput(item, expression, output_name_suffix);
}