Given the model:
> Durée <- c(6, 5, 3.5, 3, 5, 3, 2, 8, 2.5) > Note <- c(18, 16, 14, 10, 15, 13, 8, 19, 12) > model <- lm(Note ~ Durée)
I was tasked, among other things, to verify whether homoscedasticity is true.
plot(model) I was able to visualise the following graphs:
From the Residuals vs Fitted and Scale-Location plots, we can see that the line is very far from being straight, which indicates the presence of heteroscedasticity.
However, when I run the studentized Breusch-Pagan test using the command
bptest(model), I got the following output:
studentized Breusch-Pagan test data: model BP = 1.8622, df = 1, p-value = 0.1724
The test gives a p-value of 0.1724, which is greater than 0.05. This means that we can't reject the hypothesis of homoscedasticity, which contradicts, at least in my understanding, the output of the plots previously mentioned.