similar to: Calculation of ratio distribution properties

Hi! I am calculating correlation between two variables: 1. X versus Y 2. X versus Y(with a 3 steps lag) I would like to test if the correlation increase/decrease from 1 to 2 is significant or not. Is there any function in R to do this? any hints? Thanks for help :) David Ria?o Center for Spatial Technologies and Remote Sensing (CSTARS) University of California 250-N, The Barn One Shields

Hi.. I'm not sure why polygon returns an area above the standard normal curve. z <- pretty(c(-3,3), 100) ht <- dnorm(z) data <- data.frame(z=z, ht=ht) zc <- 1.645 plot(data, type="l") lines(data) t <- subset(data, z>zc) polygon(t, col="red") Thanks, Lance [[alternative HTML version deleted]]

Hello, which possibilities are available in R for simultaneous or parallel computing? I only could find biopara (http://cran.r-project.org/src/contrib/Descriptions/biopara.html) Are there other possibilities? Are there special groups working on simultaneous computing with R? Thanks Markus -- Dipl.-Tech. Math. Markus Schmidberger Ludwig-Maximilians-Universit?t M?nchen IBE - Institut f?r

I want to use the aggregate function to summarize data by a factor (my field plots), but I want the summary to be the majority level of another factor. For example, given the dataframe: Plot1 big Plot1 big Plot1 small Plot2 big Plot2 small Plot2 small Plot3 small Plot3 small Plot3 small My desired result would be: Plot1 big Plot2 small Plot3 small I

You could calculate the confidence interval of the correlation at your desired df: http://davidmlane.com/hyperstat/B8544.html The below code takes as arguments the observed correlation, N, and alpha, calculates the confidence interval and checks whether this includes 0. cor.test2=function(r,n,a=.05){ phi=function(x){ log((1+x)/(1-x))/2 } inv.phi=function(x){

Hi all, This is my first post to the developers list. As I understand it, aggregate() currently repeats a function across cells in a dataframe but is only able to handle functions with single value returns. Aggregate() also lacks the ability to retain the names given to the returned value. I've created an agg() function (pasted below) that is apparently backwards compatible (i.e.

Hi all, Consider the following function: #### my.func = function(x){ y=ifelse(x>-.5,0,ifelse(x< -.8,abs(x)/2,abs(x))) print(c(x,y)) #print what was tested and what the result is return(y) } curve(my.func,from=-1,1) #### When I attempt to find the maximum of this function, which should be -.8, I find that optimize gets stuck in the plateau area and doesn't bother testing the

Hi all, A suggestion derived from discussions amongst a number of R users in my research group: set the default column names produced by aggregate () equal to the names of the objects in the list passed to the 'by' object. ex. it is annoying to type with( my.data ,aggregate( my.dv ,list( one.iv = one.iv ,another.iv = another.iv ,yet.another.iv = yet.another.iv )

Hi all, Just thought I'd share something I discovered last night. I was interested in creating animations consisting of a series of plots and after finding very little in the usual sources regarding animation in R directly, and disliking the imagemagick method described here (http://tolstoy.newcastle.edu.au/R/help/05/10/13297.html), I discovered that if one exports the plots to a

Hi all, I understand that it is simple to create data with a specific correlation (say, .5) using mvrnorm from the MASS library: > library(MASS) > set.seed(1) > > a=mvrnorm( + n=10 + ,mu=rep(0,2) + ,Sigma=matrix(c(1,.5,.5,1),2,2) + ,empirical=T + ) > a [,1] [,2] [1,] -1.0008380 -1.233467875 [2,] -0.1588633 -0.003410001 [3,] 1.2054727 -0.620558768

Hi all, I have collected response time data from 178 participants ('sub') for each combination of 4 within-Ss factors ('con','int','tone','cue'). Additionally, I have recorded the gender of each participant, so this forms a between-Ss factor ('gender'). Normally this would be analyzed using aov:

Hi all, Hopefully this will be quick, I'm looking for pointers to packages/ functions that would allow me to calculate the power of a t.test when the DV has measurement error. That is, I understand that, ceteris paribus, experiments using measure with more error (lower reliability) will have lower power. Mike -- Mike Lawrence Graduate Student, Department of Psychology, Dalhousie

Hi all, I am extremely newbie to R. Can anybody jump-start me with any clues as to how do I get a cumulative histogram from two independent variables, cumhist(X,Y) ? -jose [[alternative HTML version deleted]]

Hello, i'm trying to find a more modern system to reproduce the functionality that was available through the Histoscope program (from Fermilab). Namely, the capability of connecting to a running process and having plots update in realtime in response to new data. Is this possible with R? Thank you, Charles Cosse [[alternative HTML version deleted]]

Hello everybody My collegue and I noticed a strange behaviour of R on different platforms. It's a simple computation, but results are rather different. On Windows XP: > floor(log(8,2)) [1] 3 which is what one should expect. Here's instead the result with Mac OS X (same version, 2.5.0 (2007-04-23)) > floor(log(8,2)) [1] 2 Is it a "bug" in R or in the operating

Hi dear R users, I'm a R beginner and I have a basic question about sequential treatments of lists. I have a time based (i.e. events are consecutive) list of values of a biological property. Like : time value 1 5 2 10 3 7 4 10 5 19 6 21 7 20 8 18 9 10 10 7 11 8 12 12 13 17 14 19 15 24 16 18 17 15 18

Hi, I have tried to download the bootstrap.tar.gz from the website below: http://cran.r-project.org/src/contrib/Old/0.50/INDEX.html I have extracted the folder to a zip file...and then use the load packages from local zip files. I use R2.0.0.0 and windows NT, i get the error: 1: error -1 in extracting from zip file 2: cannot open file `bootstrap/DESCRIPTION' ALso, when i use R CMD

Back in 2005 I had been doing most of my work in Mathcad for over 10 years. For a number of reasons I decided to switch over to R. After much effort and help from you folks I am finally "thinking" in R rather than thinking in Mathcad and trying to translating to R. Anyway, the only task I still use Mathcad for is calculations that involve physical quantities and units. For example, in

Greetings, I am working on a logistic regression model in R and I am struggling with the code, as it is a relatively new program for me. In searching Google for 'logistic regression diagnostics' I came Elizabeth Brown's Lecture 14 from her Winter 2004 Biostatistics 515 course (http://courses.washington.edu/b515/l14.pdf) . I found most of the code to be very helpful, but I am

I want to use R to run a reaction-time experiment: Something appears on the screen, I respond by typing something (one keystroke), the system measures the speed of my response. R would be great for this if only I didn't have to hit Enter to enter that keystroke. I am doing such experiments now but they require two actions per trial: hit keystroke, hit Enter. Is there some way that R can be