similar to: multiple comparison function

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

Dear R users I have a question which is only partly related to R, but I'm sending it to this list in the hope that someone with a better statistical background than mine will be kind enough to help me. It concerns multiple comparison testing in ANOVA. I know this subject has been raised before on this list, and I have looked through the relevant messages and read the article in

Hi everyone I'm trying to generate a vector of the form a <- c(1,2,3,4,1,2,3,1,2,1) where n = 5 in a general way, where n can be any positive integer. I've run out of ideas. Does anyone have any suggestions? Thanks Karen Karen Kotschy Centre for Water in the Environment University of the Witwatersrand Johannesburg Tel: 011 716-2218

Hi everyone I'm trying to generate a vector of the form a <- c(1,2,3,4,1,2,3,1,2,1) where n = 5 in a general way, where n can be any positive integer. I've run out of ideas. Does anyone have any suggestions? Thanks Karen Karen Kotschy Centre for Water in the Environment University of the Witwatersrand Johannesburg Tel: 011 716-2218

Dear helpRs Does anyone have an elegant way of doing the following: For a given numeric vector, e.g. vec <- c(3,2,6,4,7) Create a series of vectors where all but 1 of the values are replaced by 0's, e.g. vec.a <- c(3,0,0,0,0) vec.b <- c(0,2,0,0,0) vec.c <- c(0,0,6,0,0) vec.d <- c(0,0,0,4,0) vec.e <- c(0,0,0,0,7) I have looked at `replace', but can't think of a

Dear R list Would anyone be able to tell me whether it is possible to do "enhanced multidimensional scaling" (enhanced MDS) in R? In other words, something that goes beyond "cmdscale" by iteratively improving the fit between observed dissimilarities and inter-object distances, using the KYST algorithm (Kruskal, 1964). I have found several implementations of non-metric MDS

Another question: Is it possible to move R objects from one directory to another without copying the whole .RData and .Rhistory files? (I'm running under Linux) Thanks Karen Kotschy Centre for Water in the Environment University of the Witwatersrand Johannesburg Tel: 011 716-2218 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read

Hi Could somebody please explain the following to me: If x is a 10x10 matrix, typing x[3] prints all 10 values of column 3, although the length of the vector =1. Why? x[,3] and x[[3]] both give all 10 values of column 3, length=10. What is the difference between these two, actually? Thanks Karen Kotschy Centre for Water in the Environment Department of Botany University of the Witwatersrand

Dear R community Have just recently got back into R after a long break and have been amazed at how much it has grown, and how active the list is! Thank you so much to all those who contribute to this amazing project. My question: I am trying to calculate Mahalanobis distances for a matrix called "fgmatrix" >dim(fgmatrix) [1] 76 15 >fg.cov <- cov.wt(fgmatrix)

Does anyone know if an R plug-in exists for the GIS package ArcView running under Windows98 or NT? I know such a plug-in is available for S-PLUS. Thanks Karen Kotschy Centre for Water in the Environment Department of Botany University of the Witwatersrand Johannesburg South Africa Tel : +2911 716-2218 Postal address: P/Bag 3 P.O Wits 2050 South Africa

Hi R users Does anyone out there have a better/quicker way of adding a factor column to a data frame based on levels of another factor? I have a (large) data frame consisting of records for individual plants, each represented by a unique ID number. The species of each plant is indicated in the column "species", which is a factor column with many different levels (species). There are

Dear R community I sent a message out a while ago asking for help with multiple comparison tests for ANOVA's, but haven't had any response yet. I'm sending a final desperate plea. If I can't get this done in R I'm going to have to redo a whole lot of stuff in a commercial package, which I'm REALLY not keen to do! My problem is how to implement these tests in R. Below

Hello again I'm trying to put error bars onto a barplot. I've tried something that Bill Simpson suggested a while ago, ie: x<-c(1,2,3,4,5) y<-c(1.1, 2.3, 3.0, 3.9, 5.1) ucl<-c(1.3, 2.4, 3.5, 4.1, 5.3) lcl<-c(.9, 1.8, 2.7, 3.8, 5.0) plot(x,y, ylim=range(c(lcl,ucl))) arrows(x,ucl,x,lcl,length=.05,angle=90,code=3) #or segments(x,ucl,x,lcl) but I can't get it to work on a

Hello all, Here goes one of my first functions. I want to make a nonparametric multiple sample comparison with unequal sample sizes (see Zar?s Biostatistical Analysis, 3rd. Ed., pg. 201 Example 10.11, pg. 288 Example 11.10). In the real world, I want to compare samples of fish length captured with different fishing gears. After using the Kruskal-Wallis test I want to check the differences

Hi, I'm having difficulty to replicate in R a nested (hierarchical) anova example found in p. 308 of Zar, J.H. 1996. Bostatistical Analysis. Prentice Hall. 3rd ed. The example (15.1) is as follows: The variable is blood cholesterol concentration in women (in mg/100 ml of plasma). This variable was measured after the administration of one of three different drugs, each drug having been

Dear help list Does anybody know if it is possible to somehow tell R to let LaTeX handle the fonts for postscript plots produced by R? It is for a thesis and I have MANY figures. These are created by R scripts dynamically as the document is compiled, using the Make system. I see that I can `manually' specify the font family each time I call the postscript device, but I am looking for a

Hi everyone, I'm working with the Epical library, specicatly using the power test in proportions. I think this test is not working like in the book: Biostatistical Analysis (4th Edition): Jerrold H. Zar In the example 23.25. (I attach this Pic) It's not the same answer. Using the follow command don't give the same answer. library(epicalc) power.for.2p(0.75, 0.50, 50, 45, alpha =

Hi, I'm building Tukey's table using qtukey function. It happens that I can't get the values of Tukey's one degree of freedom and also wanted to eliminate the first column. The program is: Trat <- c(1:30) # number of treatments gl <- c(1:30, 40, 60, 120) # degree freedom tukval <- matrix(0, nr=length(gl), nc=length(Trat)) for(i in

Dear all I am still fishing for help on this theme. In Zar 1999 page 563-565 he describes a "Tukey-type multiple comparison" for testing among proportions. It involves comparisons of ranked proportions transformed to degrees. In the following pages there are a couple of similar comparisons. I cannot find an example of this in R. Is there such a thing? Cheers Chris

I am trying to do a Nonparametric Tukey-type multiple comparison post-hoc test to determine which groups are significantly different. I have read the dialogue on this topic from the R-help, and am still not clear why no statistical packages include this test as an option? Is it not an appropriate test to conduct on non-normally distributed data? Is the only option to calculate it by hand