I've just started studying regression analysis but I'm stuck right now.
I have a question about SSR in simple regression analysis with zero intercepts. In text book, it says SSR with zero intercepts is represented like (3.46). However I couldn't understand why $SSR$ is $\sum(\hat y)^2$ not $\sum(\hat y -\bar y)^2$. Does $\bar y=0$ in simple regression with zero intercepts?
And is it also valid that $SST=SSR+SSE$ in here? And what is $SST$ in this situation?
Thanks for everyone in advance.
