Displaying 20 results from an estimated 6000 matches similar to: "same test statistic for t-test with and without equal variance assumption"
2010 Nov 29
2
Significance of the difference between two correlation coefficients
Hi,
based on the sample size I want to calculate whether to correlation
coefficients are significantly different or not. I know that as a first step
both coefficients
have to be converted to z values using fisher's z transformation. I have
done this already but I dont know how to further proceed from there.
unlike for correlation coefficients I know that the difference for z values
is
2003 Oct 07
3
FW: Optimising code
>> I have a function that applies a wilcoxon test to 12 sets of about a quarter of a million pairs
> ... and let me guess: everything is significiant to an almost arbitrary
> value of \alpha?
:-) For each of quarter of a million sets, I do a wilcoxon between two pairs each containing twenty numbers...
I do this 12 times...
> > (and takes about 3 hours). I've replaced the
2005 Mar 16
8
Summing up matrices in a list
Dear all,
I think that my question is very simple but I failed to solve it.
I have a list which elements are matrices like this:
>mylist
[[1]]
[,1] [,2] [,3]
[1,] 1 3 5
[2,] 2 4 6
[[2]]
[,1] [,2] [,3]
[1,] 7 9 11
[2,] 8 10 12
I'd like to create a matrix M<-mylist[[1]]+mylist[[2]]
[,1] [,2] [,3]
[1,] 8 12 16
[2,] 10 14 18
2005 Jul 25
5
passing formula arguments cv.glm
I am trying to write a wrapper for the last example in help(cv.glm) that
deals with leave-one-out-cross-validation (LOOCV) for a logistic model.
This wrapper will be used as part of a bigger program.
Here is my wrapper funtion :
logistic.LOOCV.err <- function( formu=NULL, data=NULL ){
cost.fn <- function(cl, pred) mean( abs(cl-pred) > 0.5 )
glmfit <- glm(
2004 Sep 06
4
substitution in expression
I have been struggling with this problem for a while and I hope someone
could help me. Or if someone could point me to a section in the manual I
would be grateful.
x <- "my"
plot(1:10, main=expression(paste( x, Delta, "values" )))
Q : How do I get the title to say "my (triangle symbol) values" ?
The following trial-and-error produced mainly errors :
2004 Mar 15
2
make check on Solaris 8 fails due to plot
Dear all,
I am having trouble trying to install R-1.8.1 on a Sun Solaris 8
(Generic_108528-23 version) machine. The configuration was successful but
make check fails. I traced the the problem to the plot() function.
> 1 + 1
[1] 2
> capabilities()
jpeg png tcltk X11 GNOME libz http/ftp sockets
TRUE FALSE TRUE TRUE FALSE TRUE TRUE TRUE
2005 Mar 02
5
Differences between package and library terminology
Just out of curiosity, what is the difference between the terms for
package and library ? Why are we loading a package with the library()
command ?
If this is a case of RTFM, I would be happy to do so if pointed in the
right direction. I have searched the FAQ and mail archives and only came
up with http://tolstoy.newcastle.edu.au/R/help/05/02/12162.html but this
still does not explain what is
2005 Nov 06
3
How can I assign an argument to transfer whether by ref or by value?
Hello guys,
I am wondering the default way of transferring arguments in R. Is it by
value or by ref in default case, or could that be changed explicitly?
Cheers,
Xiaofan
---
Xiaofan Li
Department of Applied Mathematics and Theoretical Physics
University of Cambridge
2008 Sep 11
9
How to load functions in R
Hello,
I am trying to use self created functions in other scripts than the one
where they are stored.
For the moment I am using the following structure of commands to do
that:
1. Load the text file with the functions in the current script:
x=parse("path")
2. transform the tex in a function: f1=eval(x[1]), f2=eval(x[2]) if more
than one function is stored in the text file
3. use the
2005 Nov 09
5
How to find statistics like that.
Hi there,
Suppose mu is constant, and error is normally distributed with mean 0 and
fixed variance s. I need to find a statistics that:
Y_i = mu + beta1* I1_i beta2*I2_i + beta3*I1_i*I2_i + +error, where I_i is
1 Y_i is from group A, and 0 if Y_i is from group B.
It is large when beta1=beta2=0
It is small when beta1 and/or beta2 is not equal to 0
How can I find it by R? Thank you very much
2007 Jul 24
7
Obtaining summary of frequencies of value occurrences for a variable in a multivariate dataset.
Hi all,
If the question below as been answered before I
apologize for the posting.
I would like to get the frequencies of occurrence of
all values in a given variable in a multivariate
dataset. In short for each variable (or field) a
summary of values contained with in a value:frequency
pair, there can be many such pairs for a given
variable. I would like to do the same for several such
variables.
2003 Mar 17
4
X11 connection error in web cgi mode only
Dear all,
I am trying to create a web interface using Perl-CGI to call R plots and
to display them.
The following codes works perfectly fine when I copy and paste into the
console directly or if I save it into script.file and then R --no-save <
script.file producing the graphs.
jpeg("graph.jpeg", width=400, height=400)
plot(rnorm(100))
dev.off()
Now, I put the line system("R
2003 Dec 10
3
How to calculate standard error for a vector?
Hi all!
I 'm beginner and i develop a bio-application with VB and i need some
statistic functions!
could i calculate StdError, CoeffOfVariance, SumSquared with R langage? if
yes, what are functions to use?
I need also to use ANOVA and t-test...
Thanks for your help!
Laurent Houdusse
Analyste Programmeur
2017 Jan 24
3
Convertir programa Matlab a R sacado de Threshold Models of Collective Behavior de Michèle Lai & Yann Poltera
Estimados Usuarios-R:
Estoy convirtiendo un programa en Matlab a R.
El original lo saqu de:
Lai, M., & Poltera, Y. (2009). Lecture with computer exercises: Modelling and simulating social systems with matlab. Tech. rep., Swiss Federal Institute of Technology (December 2009). 27.
Ahora estoy convirtiendo la siguiente funcin:
function sizes = gridsizes(N,varargin)
% gridsizes(N) calculates
2012 Dec 04
1
Solve system of equations (nleqslv) only returns origin
I'm solving 4 complex equations simultaneously. Code is below. The code
returns only zero's for the solution though there should also be a non-zero
result. I'm pretty confident that the equations are correct because they
are straight from a published paper and I checked them pretty thoroughly.
The parameter values I used are from the published paper as well. Any
suggestions for how
2003 Mar 04
4
writing several command line in R console
Hi R lovers
I would like to know how to step to the next line in the R console editor
without breaking the continuity of my code
more clearly : if for example I write a function, so far i have to write the
all code inside on the same line wich may become obscure as the function is
more and more complex.
I would like to do like in the example of the manuels:
>twosam <- function(y1, y2) {
1998 Mar 03
1
":" (seq) bug -- should not always coerce to integer!
The problem seems that ":" always coerces to integer, but should not..
9.9:12
## R: [1] 9 10 11
## S-plus 3.4: [1] 9.9 10.9 11.9
## and many more examples....
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or
2010 Jul 24
1
Doubt about a population competition function
Hi,
I'm doing a function that describe two populations in competition.
that's the function that i wrote:
exclusao<-function(n10, n20, k1, k2, alfa, beta, t){
n1<-k1-(alfa*n20)
n2<-k2-(beta*n10)
if(t==0){plot(t, n10, type='b', xlim=range(c(1:t),c
(1:t)), ylim=range(n10, n20), xlab='tempo',
ylab='tamanho populacional')
points(t, n20, type='b',
2009 Mar 20
4
how to make aggregation in R ?
Hi,
I am trying to aggregate the sum of my test data.frame as follow:
testDF <- data.frame(v1 = c("a", "a", "a", "a", "a", "b", "b", "b", "b",
"b", "c", "c", "c", "c", "c", "d", "d", "d", "d",
2017 Jun 06
4
integrating 2 lists and a data frame in R
Dear Bert,
thank you for your response. here it is the piece of R code : given 3 data
frames below ---
N <- data.frame(N=c("n1","n2","n3","n4"))
M <- data.frame(M=c("m1","m2","m3","m4","m5"))
C <- data.frame(n=c("n1","n2","n3"),