[R] Help: Plsr

[Shengzhe Wu]

Dear Bjørn-Helge,

Sorry, I wrote the wrong number of observation. It should be 1184.

I saw on the book that variance is defined by sd^2. If variation is a
different concept from variance and defined by sd^2*(n-1) ? Since I
formerly took variance and variation as the same.

Thank you,
Shengzhe




Shengzhe Wu writes:

> I have a data set with 15 variables (first one is the response) and
> 1200 observations. Now I use pls package to do the plsr as below.

[...]

> Because the trainSet has been scaled before training, I think Xtotvar
> should be equal to 14, but unexpectedly Xtotvar = 16562,

Because the Xtotvar is the "total X variation", measured by sum(X^2)
(where X has been centered).  With 14 variables, scaled to sd == 1,
and 1200 observations, you should get Xtotvar == 14*(1200-1) ==
16786.  (Maybe you have 1184 observations: 14*1183 == 16562.)

--
Bj?rn-Helge Mevik