Displaying 20 results from an estimated 10000 matches similar to: "Help with correlation matrices, thresholding"
2011 Apr 09
3
In need of help with correlations
I am in need of someone's help in correlating gene expression. I'm somewhat
new to R, and can't seem to find anyone local to help me with what I think
is a simple problem.
I need to obtain pearson and spearman correlation coefficients, and
corresponding p-values for all of the genes in my dataset that correlate to
one specific gene of interest. I'm working with mouse Affymetrix
2011 Nov 16
4
Pairwise correlation
Dear All,
I am not familiar with R yet I want to use it to perform some task, hence my
posting here. I hope someone can help.
I have a set of data, genes (rows) and samples (columns). I want to do a
Pearson correlation on all the possible pairwise combinations of all the
genes (2000). Does anyone have an idea of how to execute this in R?
Thanks in advance.
--
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2012 Mar 08
4
Correlation between 2 matrices but with subset of variables
Dear All,
I have two matrices A (40 x 732) and B (40 x 1230) and would like to calculate correlation between them. I can use: cor(A,B, method="pearson") to calculate correlation between all possible pairs. But the issue is that there is one-many specific mappings between A and B and I just need to calculate correlations for those pairs (not all). Some variables in A (proteins, say p1)
2004 Sep 14
1
pairs correlations colors
I have the following problem.
I want to use pairs function and get a matrix of scatterplots with the
correlations in the upper panel and the ordinary scatterplots in the
lower panel.
Moreover, I want to have points colored in five differet ways in the
lower panel, because I have five subgroups.
In order to do that I tried to combine examples on pairs function help.
I got a colored matrix
2002 Dec 20
1
Printing correlation matrices (lm/glm)
Hi Folks,
I'm analysing some data which, in its simplest aspect,
has 3 factors A, B, C each at 2 levels.
If I do
lm1 <- lm(y ~ A*B)
say, and then
summary(lm1, corr=T)
I get the correlation matrix of the estimated coeffcients
with numerical values for the correlations (3 coeffs in this
case). Likewise with 'glm' instead of 'lm'.
However, if I do
lm2 <- lm(y ~
2009 Dec 04
2
selective subsetting of a correlation matrix
Dear All,
I have a correlation matrix say 'M' (4000x4000) for 4000 genes and I want to
subset it to 'N' (190x190) for 190 genes.
The list of those 190 genes are in variable 't'. So the idea is to read the
names of genes from variable 't' and subset the matrix M accordingly.
Any thoughts are welcome!
Best
Lee
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2013 Sep 23
0
Correlate rows of 2 matrices
Hi,
You may try:
set.seed(49)
m1 = matrix(rnorm(30), nrow = 3)
m2 = matrix(rnorm(30), nrow = 3)
?corsP<-vector()
? for(i in 1:3) corsP[i] =? cor(m1[i,], m2[i,])
?corsP
#[1]? 0.58411274 -0.02382329? 0.03760757
diag(cor(t(m1),t(m2)))
#[1]? 0.58411274 -0.02382329? 0.03760757
#or
mNew<- rbind(m1,m2)
?indx<-rep(seq(nrow(mNew)/2),2)
?sapply(split(seq_len(nrow(mNew)),indx),function(x)
2010 Jan 31
2
help on Venn's diagram
Hello!
I have this problem: I want to create a Venn's diagram with three lists of genes'names. The first is all the genome, the second a subset of it comprising all mitochondrial genes, and the third including all genes that correlate with a given gene.
This is what I do:
> library(gplots)
> A<-read.delim("F:/.../mito genes just names.txt")
>
2010 Jan 31
1
permutation analysis with randomly chosen subsets of a matrix
Hello,
here is the problem:
I want to demonstrate that, on average, the Pearson's correlations of a specified subset of genes from a huge list (>18,000 columns) are higher than any randomly chosen subset of that list. I would therefore like to do a number of tests between that specified subset and randomly chosen ones from the "mother" list.
How could I do that? What would be
2011 Jun 02
4
generating random covariance matrices (with a uniform distribution of correlations)
List members,
Via searches I've seen similar discussion of this topic but have not seen
resolution of the particular issue I am experiencing. If my search on this
topic failed, I apologize for the redundancy. I am attempting to generate
random covariance matrices but would like the corresponding correlations to
be uniformly distributed between -1 and 1.
The approach I have been using is:
2004 Apr 12
1
Very large matrices for very large genome
Hello,
I am using R to look at whole-genome gene expression data. This means
about 27,000 genes, each with a vector of numbers reflecting expression at
different tissues and times. I need to do an all against all co-expression
calculation (basically, just calculate Pearson's r for every gene-gene
pair). I try to store the result of such a thing in a 27000x27000 matrix,
but r seems not to like
2009 Mar 02
2
How to normalize to a set of internal references
Thanks for the advice. My question is more on how to do this?
Let me use a biology gene analysis example to illustrate:
In biology, there are always some house keeping genes which differ
little even at pathological conditions.
We know that at different batches, there are external factors affect
the measurements. For example, overall signal intensity might be
different due to lab reagents.
A
2008 Mar 13
1
Compare two correlations matrices
Hi there,
When I make two correlations matrices of the same size from
a <- cor(el[1:20])
b <- cor(fl[1:20])
how can I compare if this matrices are equal?
Thanks,
Martin
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2010 Jan 06
0
parcor 0.2-2 - Regularized Partial Correlation Matrices with (adaptive) Lasso, PLS, and Ridge Regression
Dear R-users,
we are happy to announce the release of our R package parcor.
The package contains tools to estimate the matrix of partial
correlations based on different regularized regression methods: Lasso,
adaptive Lasso, PLS, and Ridge Regression. In addition, parcor provides
cross-validation based model selection for Lasso, adaptive Lasso and
Ridge Regression.
More details can be found
2010 Jan 06
0
parcor 0.2-2 - Regularized Partial Correlation Matrices with (adaptive) Lasso, PLS, and Ridge Regression
Dear R-users,
we are happy to announce the release of our R package parcor.
The package contains tools to estimate the matrix of partial
correlations based on different regularized regression methods: Lasso,
adaptive Lasso, PLS, and Ridge Regression. In addition, parcor provides
cross-validation based model selection for Lasso, adaptive Lasso and
Ridge Regression.
More details can be found
2008 Sep 06
1
Test for equality of complicatedly related average correlations
Dear R-Users,
I am currently looking for a way to test the equality of two correlations
that are related in a very special way. Let me describe the situation with
an example.
- There are 100 respondents, and there are 2 points in time, t=1 and t=2.
- For each of the respondents and at each of the time points, I have
information on 10 X-variables and on 10 Y-variables.
- Based on this
2008 Oct 10
1
Correlation among correlation matrices cor() - Interpretation
Hello,
If I have two correlation matrices (e.g. one for each of two treatments) and
then perform cor() on those two correlation matrices is this third
correlation matrix interpreted as the correlation between the two
treatments?
In my sample below I would interpret that the treatments are 0.28
correlated. Is this correct?
> var1<- c(.000000000008, .09, .1234, .5670008, .00110011002200,
2011 Nov 06
2
Correlation analysis
Hi everyone,
I am new to R-project. I did search through the list for my problem but i
can't find it. I am sorry if this question has been asked.
I would like to perform a correlation analysis between a hiv data and gene
expression.
Basically, i have a file that contains: hiv_name, start_position,
end_position, chromosome. I would like to see if these data has anything to
do with the
2008 Aug 04
1
simulate data based on partial correlation matrix
Given four known and fixed vectors, x1,x2,x3,x4, I am trying to
generate a fifth vector,z, with specified known and fixed partial
correlations.
How can I do this?
In the past I have used the following (thanks to Greg Snow) to
generate a fifth vector based on zero order correlations---however I'd
like to modify it so that it can generate a fifth vector with specific
partial
2004 Nov 16
5
Difference between two correlation matrices
Hi
Now a more theoretical question. I have two correlation matrices - one
of a set of variables under a particular condition, the other of the
same set of variables under a different condition. Is there a
statistical test I can use to see if these correlation matrices are
"different"?
Thanks
Mick