[R] Help: Plsr
Shengzhe Wu
r.shengzhe at gmail.com
Mon Sep 5 15:00:20 CEST 2005
Dear Bjørn-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
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