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Scale vs Location Graph for GLM

0 votes
asked Aug 9, 2016 in STA 3043S - Decision Theory & Generalised Linear Models by Richard van Gysen (3,180 points)

When conducting model validation of a GLM, we are asked to view the graphs of our model fit (named "fit" here) using the code "plot(fit)".  It comes up with four graphs and one of them, called Scale vs Location, hasn't been taught to us.  Does anyone know how to interpret it or what it means?

1 Answer

+1 vote
answered Aug 9, 2016 by simon_rigby (4,220 points)
selected Aug 11, 2016 by Richard van Gysen
Best answer

From here:

"A scale-location plot - This plot is similar to the residuals versus fitted values plot, but it uses the square root of the standardized residuals. Like the first plot, there should be no discernable pattern to the plot"

So I guess it's just an alternative test for heteroscedacity. :)