Dear Sir,
 
Thanks for your message. My problem is in writing codes. I did ANOVA for 75000 response variables (let's say Y) with 243 predictors (let's say X-matrix) one by one with "for" loop in R. I stored the p-values of all predictors, however, i have very huge file because i have pvalues of 243 predictors for all 75000 Y-variables.
Now, i want to find some codes that autamatically select only significant X-predictors from the whole list. If you have ideas on that, it will be great help.
Thanks in advances
 
Sincerely,
Ram

--- On Wed, 1/27/10, Bert Gunter <gunter.berton@gene.com> wrote:


From: Bert Gunter <gunter.berton@gene.com>
Subject: RE: [R] selecting significant predictors from ANOVA result
To: "'ram basnet'" <basnetabc@yahoo.com>, "'R help'" <r-help@r-project.org>
Date: Wednesday, January 27, 2010, 7:56 AM


Ram:

You do not say how many cases (rows in your dataset) you have, but I suspect
it may be small (a few hundred, say).

In any case, what you describe is probably just a complicated way to
generate random numbers -- it is **highly** unlikely that any meaningful,
replicable scientific results would result from your proposed approach.

Not surprising -- this appears to be a very difficult data analysis issue.
It is obvious that you have only a minimal statistical background, so I
would strongly recommend that you find a competent local statistician to
help you with your work. Remote help from this list is wholly inadequate.

Bert Gunter
Genentech Nonclinical Statistics



-----Original Message-----
From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-project.org] On
Behalf Of ram basnet
Sent: Wednesday, January 27, 2010 2:52 AM
To: R help
Subject: [R] selecting significant predictors from ANOVA result

Dear all,

I did ANOVA for many response variables (Var1, Var2, ....Var75000), and i
got the result of p-value like below. Now, I want to select those
predictors, which have pvalue less than or equal to 0.05 for each response
variable. For example, X1, X2, X3, X4, X5 and X6 in case of Var1, and
similarly, X1, X2.......X5 in case of Var2, only X1 in case of Var3 and none
of the predictors in case of Var4.







predictors    
Var1
Var2
Var3
Var4

X1
0.00005
0.001
0.05
0.36

X2
0.0001
0.001
0.09
0.37

X3
0.0002
0.005
0.13
0.38

X4
0.0003
0.01
0.17
0.39

X5
0.01
0.05
0.21
0.4

X6
0.05
0.0455
0.25
0.41

X7
0.038063
0.0562
0.29
0.42

X8
0.04605
0.0669
0.33
0.43

X9
0.054038
0.0776
0.37
0.44

X10
0.062025
0.0883
0.41
0.45

I have very large data sets (# of response variables = ~75,000). So, i need
some kind of automated procedure. But i have no ideas.
If i got help from some body, it will be great for me.

Thanks in advance.

Sincerely,

Ram Kumar Basnet,
Ph. D student
Wageningen University,
The Netherlands.




      
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