Page 267 - Applied Statistics with R
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13.2. CHECKING ASSUMPTIONS 267
Data from Model 2
40
30
y
20
10
0 1 2 3 4 5
x
This actually is rather easy to see here by adding the fitted line to a scatterplot.
This is because we are only performing simple linear regression. With multiple
regression, a fitted versus residuals plot is a necessity, since adding a fitted
regression to a scatterplot isn’t exactly possible.
plot(fitted(fit_2), resid(fit_2), col = "grey", pch = 20,
xlab = "Fitted", ylab = "Residuals", main = "Data from Model 2")
abline(h = 0, col = "darkorange", lwd = 2)
