Displaying 20 results from an estimated 10000 matches similar to: "SAM FDR"
2011 Apr 05
0
Changing parameter in local fdr R code
I am using Efron's local fdr procedure. But, I want to change the null from
N(0,1) to N(0, 0.002). I can access the function but I have no idea what to
change. In other words, I want nulltype to be N(0,0.002) instead of N(0,1)
in his function. Anyone has any ideas. This is his code for the local fdr:
function (zz, bre = 120, df = 7, pct = 0, pct0 = 1/4, nulltype = 1,
type = 0, plot = 1,
2003 Nov 03
1
FDR in p.adjust
Hello,
I've a question about the fdr method in p.adjust: What is the threshold of
the FDR, and is it possible to change this threshold?
As I understand the FDR (please correct) it adjusts the p-values so that for
less than N% (say the cutoff is 25%) of the alternative hypothesis the Null
is in fact true.
thanks a lot for help,
+regards,
Arne
2004 Dec 19
1
limma, FDR, and p.adjust
I am posting this to both R and BioC communities because I believe there
is a lot of confusion on this topic in both communities (having searched
the mail archives of both) and I am hoping that someone will have
information that can be shared with both communities.
I have seen countless questions on the BioC list regarding limma
(Bioconductor) and its calculation of FDR. Some of them involved
2004 Dec 19
1
limma, FDR, and p.adjust
I am posting this to both R and BioC communities because I believe there
is a lot of confusion on this topic in both communities (having searched
the mail archives of both) and I am hoping that someone will have
information that can be shared with both communities.
I have seen countless questions on the BioC list regarding limma
(Bioconductor) and its calculation of FDR. Some of them involved
2004 Dec 20
1
Re: [BioC] limma, FDR, and p.adjust
Mark,
there is a fdr website link via Yoav Benjamini's homepage which is: http://www.math.tau.ac.il/%7Eroee/index.htm
On it you can download an S-Plus function (under the downloads link) which calculates the false discovery rate threshold alpha level using stepup, stepdown, dependence methods etc.
Some changes are required to the plotting code when porting it to R. I removed the
2010 Jul 13
6
permutation-based FDR
Hola a todos,
Tengo un pequeño problemilla...
Tengo unas 9000 variables que he contrastado con 1 en concreto con el test
de wilcoxon. He calculado el p-valor, y queria corregirlo con el
permutation-based FDR. He encontrado una funcion con R comp.fdr()que hace
esta corrección, pero te pide que le pongas las variables con las
observaciones y te hace el test (según he entendido). Yo solo quiero
2006 Nov 10
4
Selective subsetting
Hi all,
Here's an interesting (for me, at least!) problem I came across:
I have a correlation matrix, let's say with 6 variables, A to F, as column
headings and the same 6 as row headings.
The matrix is filled with correlation coefficients. Therefore, the diagonal
is all 1's, and each of the two triangles formed by the diagonal has the
same 15 correlation coefficients.
I need to
2004 Dec 20
1
[BioC] limma, FDR, and p.adjust
You asked the same question on the Bioconductor mailing list back in August. At that time, you
suggested yourself a solution for how the adjusted p-values should be interpreted. I answered
your query and told you that your interpretation was correct. So I'm not sure what more can be
said, except that you should read the article Wright (1992), which is cited in the help entry for
p.adjust(),
2010 Oct 07
1
FDR
Dear R users,
I am wondering about the following results:
> p.adjust(c(0.05,0.05,0.05),"fdr")
[1] 0.05 0.05 0.05
> p.adjust(c(0.05,0.04,0.03),"fdr")
[1] 0.05 0.05 0.05
Why does p.adjust(..., "fdr") not adjust p-values, if they are constant?
Does somebody have an explanation or can point to a reference?
Thanks in advance,
Will
2007 Feb 28
2
topTable function from LIMMA
Dear R-Help,
I am using the function "topTable" from the LIMMA package. To estimate
adjusted P-values there are several options (adjust="fdr" , adjust="BH")
as shown below:
topTable(fit, number = 10, adjust = "BH", fit$Name)
I guess any of these options (fdr, BH, etc.) is using a default of
FDR=0.05 which is quite conservative (i.e., very
2018 Jun 08
2
XRay FDR mode doesn’t log main thread calls
Hello,
I am initializing FDR mode and finalizing/flushing the buffers manually.
XRay does not log calls from the main thread unless there is a function
call after __xray_log_finalize(). This behavior is abnormal since one would
expect the trace file to contain all function calls made up to the point
when __xray_log_finalize() is called. To demonstrate this behavior, I have
taken the test case
2010 Aug 08
1
p.adjust( , fdr)
Hello,
I am not sure about the p.adjust( , fdr). How do these adjusted p-values
get?
I have read papers of BH method. For independent case, we compare the
ordered p-values with the alfa*i/m, where m is the number of tests. But I
have checked that result based on the adjusted p-values is different with
that by using the independent case method.
Then how do the result of p.adjust( , fdr) come?
And
2008 Jan 15
0
FDR for hypergeometric tests
Dear list,
I have performed several tests for the hypergeometric distribution
using phyper() for some gene annotation categories as follows
>phyper(26,830,31042,337, lower.tail=F)
>phyper(16,387,31042,337, lower.tail=F)
.
.
.
I am only running some selected categories but I would like to correct
this value for multiple testing since I
have 3121 possible tests according to 3121
2005 Aug 16
1
permutated p values vs. normal p values
Hi, I am performing Cox proportional hazards
regression on a microarray dataset with 15000 genes.
The p values generated from the Cox regression (based
on normal distribution of large sample theory) showed
only 2 genes have a p value less than 0.05. However,
when I did a permutation on the dataset to obtained
permutated p values, and it turned out about 750 genes
had a permutated p value less than
2005 Sep 22
0
FW: FDR analyses: minimum number of features
Dear Dr. Graves
Many thanks for your response. FDRs and their associated q values do
differ from Type I error rates and P values (See Storey and Tibshirani
PNAS 2003;100:9440-5). It is an approach that is rapidly gaining
popularity in the analysis of genomic data where we have massive numbers
of covariates measured on a comparatively modest number of subjects. To
my mind it is a real advance
2007 Jan 23
3
the value of Delta
Dear all,
I am running R 2.4.1.
> library(siggenes);
> library(multtest);
> cl<-rep(c(0,1),c(3,3));
> sub<-exprs(AffyExpData[,c(1:3,7:9)]);
> gn<-geneNames(AffyRAwData);
> sam.out<-sam(sub,cl,rand=123,gene.names=gn);
We're doing 20 complete permutations
> sam.out
SAM Analysis for the Two-Class Unpaired Case Assuming Unequal Variances
Delta p0
2004 Nov 22
1
Questions of Significance Analysis of Microarrays(SAM){siggenes}
Dear All:
Significance Analysis of Microarrays(SAM)
As we know sam do multiple t.test as following
## Default S3 method:
t.test(x, y = NULL, alternative = c("two.sided", "less", "greater"),mu = 0,
paired = FALSE, var.equal = FALSE,conf.level = 0.95, ...)
var.equal: a logical variable indicating whether to treat the two variances
as being equal. If 'TRUE'
2006 Aug 10
3
Multiple density curves
Hi,
I am new to R...a recent convert from SAS.
I have a dataset that looks like this:
SEQ A1 A2
A 532.5 554.5
B 25.5 35.5
C 265.2 522.2
D 245.55 521.56
E 546.52 141.52
F 243.25 32.56
G 452.55 635.56
H 15.14 16.54
I 543.4 646.56
J 54.4 654.5
K 646.5 64.54
L 645.4 614.46
M 646.54 634.46
I want to make a histogram
2018 Jun 11
2
XRay feature – fdr log flushing
Hello,
Also, I’ve noticed that FDR mode doesn’t flush to a log unless
programmatically configured to do so unlike basic mode, which flushes by
default. Would it be possible to add this feature as well?
Thanks,
Henry
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2012 Mar 30
1
Help with the lumi R package
Hi all,
My name is Amy, I am a masters student in Bioinformatics at North Carolina
State University. I am working on a project and I am trying to use the lumi
R package for microarray data analysis. I have shown the sample code here
and have questions about modifying the sample code for my own data.
lumi package in R, example.lumi, the sample data has 8000 features and 4
samples
I have