st: Two-way anova vs linear regression: how can I understand Partial SS

 From "Hoogendoorn, Adriaan" <[email protected]> To "[email protected]" <[email protected]> Subject st: Two-way anova vs linear regression: how can I understand Partial SS Date Mon, 4 Jan 2010 11:22:45 +0100

```Dear Statalist,

My question is more about statistics than about Stata, but also so elementary
that I'd like to post this problem here.

In ANOVA I have difficulty in understanding the notion of Partial Sum of
Squares - being the default option in Stata's anova.

In understanding statistical methods, I use linear regression (OLS) as a
reference method, since regression allows me to draw pictures in my mind
and is a method that I feel comfortable with. ANOVA is not so intuitive
to me. But since the underlying methods of OLS and ANOVA are essentially
the same (both General Linear Models - GLMs), I regard the difference
between these methods as "different interfaces" to the same GLM.

My question is:
'How can I obtain the Partial Sum of Squares of each of
the variables in the case of a two way anova with interaction by us of
regression analysis?'

or - more applied - :
How do I get the Partial SS of foreign in:
*---------------- begin example --------------------------
sysuse auto, clear
anova mpg foreign rep78 foreign#rep78
*------------------ end example -----------------------------
using regression analysis?

Kind regards,