similar to: how to create cumulative histogram from two independent variables?

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

Hello there, I am using R to plot some cumulative histogram for my data. Please help in this case. Thank you Lisa Wang Princess Margaret Hospital Toronto phone 416 946 4501 ext.4883

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 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:

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]]

Hi all, Looking to calculate the expected mean and variance of a ratio distribution where the source distributions are gaussian with known parameters and sample values are correlated. I see (from wikipedia: http://en.wikipedia.org/wiki/ Ratio_distribution#Gaussian_ratio_distribution) that this calculation is quite involved, so I'm hoping that someone has already coded a function to

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

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

Does R do cumulative frequency distribution plots? -- Tommy E. Cathey, Senior Scientific Application Consultant High Performance Computing & Scientific Visualization SAIC, Supporting the EPA Research Triangle Park, NC 919-541-1500 EMail: cathey.tommy at epa.gov My e-mail does not reflect the opinion of SAIC or the EPA. Federal Contact - John B. Smith 919-541-1087 - smith.johnb at epa.gov

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

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

Hi list, this is my second try for first post on this list (I tried to post via email and nothing appeared in my email-inbox, so now I try to use the nabble-web-interface) - I hope that you will only have to read one post in your inbox! Okay, my question ... I was able to plot a histogram and add the density()-line to this plot. I was able to plot a cumulative form of this histogram. Yet, I was

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

hi all: ecdf() is the empirical cumulative distribution function, but I need the INVERSE cumulative distribution. how can I calculate it? thank you in advance /salva