similar to: concordance correlation coefficient using R

Dear R-helpers, I am developing a Mixed-Effects model for a study of immunoassays using 'lme4' library. The study design is as follows: 10 samples were run using 7 different immunoassays, 3 times each, in duplicates. Data attached. I have developed the following model: c.lme <- lmer(Result~SPL + (SPL|Assay/Run) -1, data=data) This model has excellent predictions - the Rsquared of

Hi dear R-listers, I'm trying to fit a 3-level model using lme in R. My sample size is about 2965 and 3 factors: year (5 levels), ssize (4 levels), condition (2 levels). When I issue the following command: > lme(var~year*ssize*condition,random=~ssize+condition|subject,data=smp,method ="ML") I got the following error: Error in logLik.lmeStructInt(lmeSt, lmePars) :

Dear all, As I said in my previous email I have just upgraded to R 2.14.0 on Windows 7. I have just run the 'coxph' function and notice that a Concordance statistic is produced. Is there any way to extract this information from the output? E.g. can I call the concordance value independently of calling the output? Many thanks, Laura [[alternative HTML version deleted]]

Hello everyone. This is a question regarding generation of the concordance index (c index) in R using the function rcorr.cens. In particular about interpretation of its direction and form of the 'predictor'. One of the arguments is a "numeric predictor variable" ( presumably this is just a *single* predictor variable). Say this variable takes numeric values.... Am I

Hello R-devel, I am currently attempting to implement an API similar to data.table wherein single bracket subsetting can accept an unquoted expression to be evaluated in the context of my object. A simple example from the data.table package looks like this: DT <- data.table(col1 = c('a', 'b', 'c'), col2 = c('x', 'y', 'z')) DT[col1 ==

Help. - Is there a beginner's manual for R? - How do i analyse gene expression data using R, to generate a dendrogram. I would greatlyy appreciate every bit of input. -- BEST Paul [[alternative HTML version deleted]]

Hello group, my question is deciding what test would be appropriate for following question. An experiment 'A' yielded 3200 observations of which 431 are significant. Similarly, using same method, another experiment 'B' on a different population yielded 2541 observations of which 260 are significant. There are 180 observations that are common between significant observations of A

Dear I estimate a sample selection model using the Clayton copula and Burr and Gaussian marginal. I need to derive ther Kendall'sw tau from the concordance coefficient by integration. I came across a way to do that in R long time ago but cannot find it again. Can somewone tell me what to read and what to use? Thank you. Steven Yen

I know that there are quite a few packages out that there for cluster analysis. The problem that I am facing is finding a package that will not incorporate all my samples into clusters but just the samples that fit a threshold (that I have not set yet and may need help finding the right level) for genotyping. It should be able to "no call" samples outside the clusters. It also needs to

Hi everyone. I am having problems with NULL values. I understand in R one can command the program to skip null values. Can some one help me on the command line for that. Do i enter is as part of the string in: a<- read.table("filename.csv", header = T, row.names=1, sep=","); My problem is largely when i attempt to use correlation for my data... xcc <- cor(a); The

Hello R-Community, I am a rookie in R and I am fascinated with the power of bio computing by R. I am analysing gene expression data from Real time PCR. I have used absolute gene quantitation to measure gene copy number in all my transcripts. All my data has been normalised them to a housekeeping gene, which is constitutive expressed. My problem is as follows. After normalising some of the genes

Hi, further down from the problem I asked about yesterday I encounter the following problem (please appologize for the lengthy mail - I have not found a brief example making the issue clear): - using R packages making use of namespaces & - S4 classes when using --with-package-versions in the install call: Pkgs install ok and the first pkg 'base' can be loaded in R

Dear all, The default plotting method for hclust trees looks just fine for few objects like in the example dataset. But when it comes to many features (eg some 1000 and more - I'm trying to visualize clustered microarray data) it renders a tree, that one cannot inspect, because of overlapping text and lines. My question is, is there a way or a plotting parameter for plotting a tree which is

Greetings ~ I need some assistance determining an appropriate approach to analyzing multivariate binary response data, and how to do it in R. The setting: Data from an assay, wherein 6-hours-post-fertilization zebrafish embryos (n=20, say) are exposed in a vial to a chemical (replicated 3 times, say), and 5 days later observed for the presence/absence (1/0) of defects in several organ systems

Dears, I'm a college student and In doing my statistics homework. I use R with SEM package as my tool for sem analysis, but my teacher told me AMOS is more suitable for such analysis. Could someone help tell me whether it is true that some commercial software is better accepted in academic fields? Sorry if I should not post such topics here. -- Best Regards, Reeyarn T. Lee Accounting

Hallo! Does anybody know how to calculate a sample size estimation for proportions with continuity correction? ? I only found EpiR which seems to calculate without continuity correction: library(epiR) epi.studysize(treat = .65, control = .50, n = NA, sigma = NA, power = 0.80, r = 1, conf.level = 0.95, sided.test = 2, method = "cohort") $n [1] 340 Thanks! Karl

Hi again Sorry, in looking again at sammon and isoMDS I see that they seem to do exactly what I want, except that they are non-metric, which means, as I understand it, that they relate the rank orders of the variables rather than the actual distances. Could I use these non-metric MDS packages even if my distances are metric? Thanks Karen -- Karen Kotschy Centre for Water in the Environment

I'm looking at Pinheiro & Bates "Mixed-Effects Models in S and S-PLUS" at the moment. Several datasets are used, one of which is called "PBIB" (a partially balanced incomplete block design). All the other datasets can be found somewhere or other in R. However, I cannot locate PBIB, and it does not seem to be mentioned in the latest edition of the R Full Reference

Hello, I have climatic data of various years with many missing values. I would like to know what tools in R are most suited to estimate this missing values. (New in R and quite new on statistics). Thanks, G

Hi all, I have relatively small dataset on which I would like to perform a PCA. I am interested about a package that would also combine a method for determining the number of components (I know there are plenty of approaches to this problem). Any suggestions about a package/function? thanks, Nick -- View this message in context: