Displaying 20 results from an estimated 5000 matches similar to: "Determining the correlation coefficient?"
2008 Feb 11
2
RGTK2 and glade on Windows - GUI newbie
Hallo,
I'd like to write a GUI (first choice with GTK+).
I've surfed through the R- an Omegahat-Pages, because I'd like to use
RGTK2, GTK 2.10.11 in combination with glade on Windows XP (perhaps later
Unix, Mac).
I've found a lot of different information. Because of the information I'm
not sure, if this combination is running on Windows XP and I'm unsure how
it works.
Is
2010 Jan 05
1
bootstrapping a matrix and calculating Pearson's correlation coefficient
Hi All,
I have got matrix 'data' of dimension 22000x600. I want to make 50
independent samples of dimension 22000x300 from the original matrix 'data'.
And then want to calculate pearsons CC for each of the obtained 50 matrices.
It seems it is possible to do this using 'boot' function from library boot
but I am not able to figure out how? I am really stuck. Please help!
2007 Jun 12
4
Generating artificial datasets with a specific correlation coefficient.
I need to create artificial datasets with specific correlation
coefficients (i.e. a dataset that returns r = 0.30, etc.) as examples
for a lab I am teaching this summer. Is there a way to do that in R?
Thanks.
Jim Milks
Graduate Student
Environmental Sciences Ph.D. Program
136 Biological Sciences
Wright State University
3640 Colonel Glenn Hwy
Dayton, OH 45435
[[alternative HTML version
2004 Apr 10
1
confidential interval of correlation coefficient using bootstrap
I tried 2 methods to estimate C.I. of correlation coefficient of variables x and y:
> x <- c(44.4, 45.9, 41.9, 53.3, 44.7, 44.1, 50.7, 45.2, 60.1)
> y <- c( 2.6, 3.1, 2.5, 5.0, 3.6, 4.0, 5.2, 2.8, 3.8)
#METHOD 1: Pearson's
**********************************************************
> cor.test(x, y, method = "pearson", conf.level = 0.95)
Pearson's
2009 May 26
2
(OT) Does pearson correlation assume bivariate normality of the data?
Dear all,
The other day I was reading this post [1] that slightly surprised me:
"To reject the null of no correlation, an hypothsis test based on the
normal distribution. If normality is not the base assumption your
working from then p-values, significance tests and conf. intervals
dont mean much (the value of the coefficient is not reliable) " (BOB
SAMOHYL).
To me this implied that in
2011 Oct 03
2
extracting p-values in scientific notation
Dear all
How does print.htest display the p-value in scientific notation?
> (x <- cor.test(iris[[1]], iris[[3]]))
Pearson's product-moment correlation
data: iris[[1]] and iris[[3]]
t = 21.65, df = 148, p-value < 2.2e-16
alternative hypothesis: true correlation is not equal to 0
95 percent confidence interval:
0.8270 0.9055
sample estimates:
cor
0.8718
Above the p-value comes
2005 Sep 27
1
Simulate phi-coefficient (correlation between dichotomous vars)
Newsgroup members,
I appreciate the help on this topic.
David Duffy provided a solution (below) that was quite helpful, and came
close to what I needed. It did a great job creating two vectors of
dichotomous variables with a known correlation (what I referred to as a
phi-coefficient).
My situation is a bit more complicated and I'm not sure it is easily
solved. The problem is that I must
2009 Feb 19
1
Bug in predict function for naiveBayes?
Dear all,
I tried a simple naive Bayes classification on an artificial dataset, but I
have troubles getting the predict function to work with the type="class"
specification. With type= "raw", it works perfectly, but with type="class" I
get following error :
Error in as.vector(x, mode) : invalid 'mode' argument
Data : mixture.train is a training set with 100
2005 Sep 09
2
Simulate phi-coefficient
Looking for help with the following problem.
Given a sample of zeros and ones, for example:
> VECTOR1<-rep(c(1,0),c(15,10))
> VECTOR1
[1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
How would I create a new sample (VECTOR2) also containing zeros and
ones, in which the phi-coefficient between the two sample vectors was
drawn from a population with a known
2004 Jun 25
2
Simulating from a Multivariate Normal Distribution Using a Correlation Matrix
Hello,
I would like to simulate randomly from a multivariate normal distribution using a correlation
matrix, rho. I do not have sigma. I have searched the help archive and the R documentation as
well as doing a standard google search. What I have seen is that one can either use rmvnorm in
the package: mvtnorm or mvrnorm in the package: MASS. I believe I read somewhere that the latter
was
2010 Dec 06
5
Urgent Help with R calculation correlation coefficient
Hi,
I am trying to calculate correlation coefficient for gene expression data.
Tab delimited file looks like this
Id v1 v2 v3
df 56 90 45
gh 87 98 78
ty 89 78 67
I used this code
[code]
gse20437 <- read.csv("C:/Users//Desktop/data/GSE20437_matrix.txt",header =
TRUE, sep = ",", strip.white = TRUE)
gsecor <- cor(gse20437, method
2007 Nov 16
1
generate multivariate F with specified correlation matrix
Dear all,
In MATLAB, to generate multivariate F with specified correlation matrix Pn I can use the code such as
Z = mvnrnd([0 0 0 0 0], Pn, N);
U = normcdf(Z,0,1);
X = [finv(U(:,1),5,15) finv(U(:,2),5,15) finv(U(:,3),5,15) finv(U(:,4),5,15) finv(U(:,5),5,15)];
Is there something similar in R?
Thank you for your time.
2004 Feb 16
1
labRow/labCol options in heatmap()
The function heatmap() allows to specify row/column labels
via the options labRow/labCol. From the code of heatmap(),
I understand that when no labels are specified, the row/column
labels (or indices) of the input matrix are taken as labels and
re-ordered together with the rows and columns of the matrix before
plotting, whereas labels supplied via labRow/labCol are plotted
in the original order.
2004 Jul 07
1
negative p-value from fisher.test() (PR#7064)
Full_Name: Anja von Heydebreck
Version: 1.9.1
OS: Linux
Submission from: (NULL) (155.250.128.25)
I obtained a negative p-value from the fisher.test() function:
> fisher.test(matrix(c(14576,3023,89,68),2), alternative="g")$p.value
[1] -8.426593e-13
With R 1.8.1, I got a p-value of -6.239231e-12 for this example.
Anja von Heydebreck
2007 Jul 13
1
correlation matrix difference
Hi, I have got four correlation matrix. They are the same set of variables
under different conditions. Is there a way to test whether the correlation
matrix are significently different among each other? Could
anyone give me some advice?
--
View this message in context: http://www.nabble.com/correlation-matrix-difference-tf4073868.html#a11578046
Sent from the R help mailing list archive at
2006 Jun 28
1
Simulate dichotomous correlation matrix
Newsgroup members,
Does anyone have a clever way to simulate a correlation matrix such that
each column contains dichotomous variables (0,1) and where each column
has different prevalence rates.
For instance, I would like to simulate the following correlation matrix:
> CORMAT[1:4,1:4]
PUREPT PTCUT2 PHQCUT2T ALCCUTT2
PUREPT 1.0000000 0.5141552 0.1913139 0.1917923
PTCUT2
2001 Aug 22
1
cutree (PR#1067)
Full_Name: Anja von Heydebreck
Version: 1.3.0
OS: Alpha Unix
Submission from: (NULL) (141.14.19.61)
Hi,
I repeatedly obtained meaningless results from the function 'cutree'
in the 'mva' package, when the argument 'h' was greater or equal to
the maximum height occuring:
> library('mva')
> y
[,1] [,2] [,3] [,4]
[1,] 0 1 -1 1
[2,] 0 -1
2013 Mar 28
2
hierarchical clustering with pearson's coefficient
Hello,
I want to use pearson's correlation as distance between observations and
then use any centroid based linkage distance (ex. Ward's distance)
When linkage distances are formed as the Lance-Williams recursive
formulation, they just require the initial distance between observations.
See here: http://en.wikipedia.org/wiki/Ward%27s_method
It is said that you have to use euclidean
2011 Aug 19
2
display only the top-right half of a correlation matrix?
Dear all
Is there an easy way to display only one half (top-right or
bottom-left) of a correlation matrix?
> require(Hmisc)
> rcorr(as.matrix(mtcars[ , 1:4]))
mpg cyl disp hp
mpg 1.00 -0.85 -0.85 -0.78
cyl -0.85 1.00 0.90 0.83
disp -0.85 0.90 1.00 0.79
hp -0.78 0.83 0.79 1.00
n= 32
P
mpg cyl disp hp
mpg 0 0 0
cyl 0 0 0
disp 0 0
2009 Sep 20
4
correlation help
Dear group,
I have a matrix like the following:
Name Sample1 sample2 sample3 sample4 ..... sample(n)
nm1 10.5 13.5 30 31
nm2 8 11 34 29
nm3 9 10.3 27.8 35
nm(j)
I want to be able to calculate correlation between all pairs of names.
For example (nm1,nm2),