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Why does R CMD INSTALL work for some packages (e.g., lme4) but not others (e.g., nlme)? Thanks, Gang

Hi experts, I just started to learn R today, and tried to work with an add-on package sem. I have a version of 2.3.1 on MacOS X 10.4.6 with sem put under /Library/Frameworks/R.framework/Versions/2.3/Resources/library However when I typed library(sem) the following error showed up: Error in library(sem) : 'sem' is not a valid package -- installed < 2.0.0? Why is this? Thank

I want to create a list based on the information from a data.frame, Model. So I tried the following: MyList <- list(colnames(Model)[2] = levels(Model$(colnames(Model)[2]))) but it failed with an error: Error: unexpected '=' in "list(colnames(Model)[2] =" I have the following problems with this command line: (1) I wanted to use colnames(Model)[2] as a tag for the list:

For some unknown reason I stopped receiving any messages from the R- help mailing list. See if this test gets through. Thanks, Gang

Suppose I have a 4-D array X with dimensions (dx, dy, dz, dp). I want to collapse the first 3 dimensions of X to make a 2-D array Y with dimensions (dx*dy*dz, dp). Instead of awkward looping, what is a good way to do this? Is there a similar function like reshape in Matlab? Thanks, Gang

I want to run deconvolution of a time series by an impulse or point-spread function through Wiener filter, regularized filter, Lucy-Richardson method, or any other approaches. I searched the CRAN website and the mailing list archive, but could not find any package for such a deconvolution analysis. Does anybody know an existing R function for deconvolution? TIA, Gang

Suppose I have a mixed-effects model where yij is the jth sample for the ith subject: yij= beta0 + beta1(age) + beta2(age^2) + beta3(age^3) + beta4(IQ) + beta5(IQ^2) + beta6(age*IQ) + beta7(age^2*IQ) + beta8(age^3 *IQ) +random intercepti + eij In R how can I get an F test against the null hypothesis of beta6=beta7=beta8=0? In SAS I can run something like contrast age*IQ 1,

This must be very simple, but I'm stuck. I have a command line in R defined as a variable of a string of characters. How can I convert the variable so that I can execute it in R? Really appreciate any help, Gang

I do not think anyone has answered this. > I'm trying to run a simple one-way ANCOVA with the lmer > function in R package lme4, but have encountered some > conceptual problem. The data file MyData.txt is like this: > > Group Subj Cov Resp > A 1 3.90 4.05 > A 2 4.05 4.25 > A 3 4.25 3.60 > A 4 3.60 4.20 > A 5 4.20 4.05 > A 6 4.05 3.85

Hi all, I am a newbie of R, and have a very simple question. When I run the following t test result = t.test(weight ~ group) If I want to get the t value, I can do tvalue = result$statistic with tvalue being the following: t 1.191260 However, if I just want the number 1.191260, not the character "t", how can I achieve that? Thank you very much, Gang

I want to identify whether a variable is character(0), but get lost. For example, if I have > dd<-character(0) the following doesn't seem to serve as a good identifier: > dd==character(0) logical(0) So how to detect character(0)? Thanks, Gang

I'm running a categorical data analysis with a two-way design of nominal by ordinal structure like the Political Ideology Example (Table 9.5) in Agresti's book Categorical Data Analysis. The nominal variable is Method while the ordinal variable is Quality (Bad, Moderate, Good, Excellent). I rank/quantify Quality with another variable QualityR (1, 2, 3, 4), and run the following:

I want to pass a predefined string ww ("fa*fb+fc") to function lme so that I can run > lme(y ~ fa*fb+fc, random = ~1|subj, model) I've tried something like > lme(y ~ paste(ww), random = ~1|subj, model) and > lme(y ~ sprintf(ww), random = ~1|subj, model) but both give me the following error: Error in model.frame(formula, rownames, variables, varnames, extras,

Sorry to hijack this thread. I have a similar but slightly different situation. Using the original poster's example, how to elegantly get the mean of column V2 when column V1 is either A or C and F1 is 0? Thanks, Gang On Nov 13, 2007, at 5:30 AM, Petr PIKAL wrote: > Hi > > r-help-bounces@r-project.org napsal dne 13.11.2007 10:59:09: > >> Dear list, >> >> I

Based on the examples I've seen in using statistical analysis packages such as lmer, it seems that people usually tabulate all the input data into one file with the first line indicating the variable names (or labels), and then read the file inside R. However, in my case I can't do that because of the huge amount of imaging data. Suppose I have a one-way within-subject ANCOVA with