[R] PCA with NA
Birgit Lemcke
birgit.lemcke at systbot.uzh.ch
Wed Nov 28 18:05:01 CET 2007
Hello,
unfortunately I can not find the pcaMethods package.
Birgit
Am 26.11.2007 um 16:26 schrieb Kevin Wright:
> The pcaMethods package offers a collection of different algorithms for
> PCA, some of which (NIPALS and others) can be used on data that have
> missing values.
>
> Kevin Wright
>
>
> On Nov 24, 2007 4:59 PM, Hartmut Oldenbürger <jcleese at liteline.de>
> wrote:
>> Hi Birgit, and All
>>
>> Possibly you should not consider the case completed ;-)
>> There is an important alternative to imputing means, or estimates
>> from
>> first or second order
>> regression (Frane, Psychometrica, BMDP): partial-least-squares
>> (Wold),
>> which uses as much
>> information from the data as possible to estimate the principal
>> components, or the missing data.
>>
>> Stephane Dray, also from Lyon, provides 'nipals' here:
>> http://biomserv.univ-lyon1.fr/~dray/software.php
>> There is also an interesting paper. - In case, you use PLS to
>> estimate
>> and impute, set the
>> number of factors as high as reasonably possible, e.g. m-1, when m is
>> the number of variables.
>> best - Hartmut
>> Oldenbürger
>> ---
>> holdenb1 at uni-goettingen.de
>> http://www.wipaed.wiso.uni-goettingen.de/~holdenb1
>>
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
Birgit Lemcke
Institut für Systematische Botanik
Zollikerstrasse 107
CH-8008 Zürich
Switzerland
Ph: +41 (0)44 634 8351
birgit.lemcke at systbot.uzh.ch
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