similar to: same test statistic for t-test with and without equal variance assumption

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"),