search for: mardia

In the R code of Mardia's test, what does the line " x1 = x[x[, p] == i, -p]" mean? Thanks a lot! function (x) { p = dim(x)[2] f = p - 1 clases = length(table(x[, p])) for (i in 1:clases) { x1 = x[x[, p] == i, -p] ndat = dim(x1)[1] mo3 = mo3(x1) mard1 = n...

Dear all, I got this error message > library(dprep) > mardia(Savg) Error in cov(data) : 'x' is empty But with the same data, I got > library(mvnormtest) > mshapiro.test(Savg) Shapiro-Wilk normality test data: Z W = 0.9411, p-value = 0.6739 What does the error message "Error in cov(data) : 'x' is empty" mean? T...

...data? Or implementation details of the R oblimin function in GPArotation? Jackson writes about 'raw oblimin', 'normal oblimin' and 'direct oblimin' and I do not know how that relates to the R oblimin implementation. I have also tried varimax on data and results given by Mardia in his 'Multivariate analysis' book Table 9.4.1. Mardia uses the communalities from the factor analysis in the expression for the varimax rotation. I dont see how the R varimax function can handle the communalities. I dont have the book right at hand, but I believe this R code represent...

Good Night I made different test to check normality and multinormality in my dataset, but I don´t know which test is better. To verify univariate normality I checked: shapiro.test, cvm.test, ad.test, lillie.test, sf.test or jaque.bera.test and To verify multivariate normal distribution I use mardia, mvShapiro.Test, mvsf, mshapiro.test, mvnorm.e. I have a dataset with almost 1000 data and 9 variables, in both cases the result is non-normality. For this reason, I transformed data with bcPower function and I want to check normality again. I really appreciate your help. Thanks. [[alternative...

...e xcoef and ycoef components of cancor might themselves be restricted to the appropriate columns (1:rank). This might affect some existing code, although any code that uses the non-informative columns has got to be broken, hasn't it?! Can I also suggest an extra reference for the help page: Mardia, K. V., J. T. Kent and J. M. Bibby (1979). Multivariate Analysis, London, Academic Press Ltd, ch. 10. Cheers, Jonathan. -- Jonathan Rougier Science Laboratories Department of Mathematical Sciences South Road University of Durham Durham DH1 3LE tel:...

r-help at stat.math.ethz.ch on Saturday, May 13, 2006 at 6:00 AM -0500 wrote: >>One of my friends recently wrote his PhD thesis from University of >>Leeds under Kanti Mardia's direction. I bet your friend was really angling for that. -- Alan B. Cobo-Lewis, Ph.D. (207) 581-3840 tel Department of Psychology (207) 581-6128 fax University of Maine Orono, ME 04469-5742 alanc at maine.edu http://www.umaine.edu/visualperception

hello all sorry for the following "none" R related question. does anyone know of a reference to calculate the following identity: |I + ABC| where I is an identity matrix and A, B,C may not have to be square matrices? you help will be greatly appreciated. H. V. Henderson; S. R. Searle SIAM Review, Vol. 23, No. 1. (Jan., 1981), pp. 53-60. provides a result to

Dear R developers, there appears to be a small problem with function cmdscale: for non-Euclidean distance matrices, using option add=FALSE (the default), cmdscale misses the smallest eigenvalue. This affects GOF statistic g.1 (See Mardia, Kent + Bibby (1979): Multivariate Analysis, eq. (14.4.7). The corresponding formula in Cox + Cox (2001): Multidimensional Scaling, 2nd ed., p 38, would seem to contain a misprint, it should be n instead of n-1.) Example: R> cmdscale(eurodist, eig=TRUE)$GOF [1] 0.7968344 0.8679134 The full...

Hi, there. I have two questions about the diagnostics in multivarite statistics. 1. Is there any diagnostics tool to check if a multivariate sample is from multivariate normal distribution? If there is one, is there any function doing it in R? 2. Is there any function of testing if two multivariate distribution are same, i.e. the multivariate extension of Kolomogrov-Smirnov test? Thanks for

...ach: it seems that wind direction and wind speed are autocorrelated over . But it seems to be due to a non stationarity since computing the autocorrelation on first derivative destroys everything (correlation of wind direction is performed using the circular-circular correlation coeff as defined by Mardia 1976). - Correlate with other meteo stations: this is a problem because wind patterns are affected by topography for instance and even nearby stations may have different wind patterns. Also the correlation between meteo stations is questionable since a N wind will first affect Northern stations wh...

I have some images of bugs (insects) with many bugs in each image. I want to count the number of bugs and to have an estimate of the area of each one. I've tried searching for an R package to do so with no success. Is this a task that I should pursue doing in R or should I restrict myself to specific image analysis software (e.g. ImageJ)?. The reason I consider R would be a good choice is

...tation}{the matrix of variable loadings (i.e. a matrix whose columns contain the eigenvectors). The function princomp returns this in the element \code{loadings}.} \item{x}{if retx is true the value of the rotated data (the data multiplied by the \code{rotation} matrix) is returned.} } \references{ Mardia, K. V., J. T. Kent, J and M. Bibby (1979), \emph{Multivariate Analysis}, London: Academic Press. Venerables, W. N. and B. D. Ripley (1994). \emph{Modern Applied Statistics with S-Plus}, Springer-Verlag. } \seealso{ \code{\link{princomp}}, \code{\link{prcomponents}}, \code{\link{cor}}, \code{\link...

Dear , I want to import Excel data (.XLS). Can you help me to this. Best regards. Nour-Eddine HAKIM -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at

Thanks Dimitris!!! That's much clearer now. Still have a lot of work to do this weekend to understand every bit but your code will prove very useful. Cheers, Aziz -----Original Message----- From: Dimitrios Rizopoulos [mailto:Dimitris.Rizopoulos at med.kuleuven.be] Sent: May 12, 2006 4:35 PM To: Chaouch, Aziz Subject: RE: [R] Maximum likelihood estimate of bivariate

Dear List: I have a question regarding an MDS procedure that I am accustomed to using. I have searched around the archives a bit and the help doc and still need a little assistance. The package isoMDS is what I need to perform the non-metric scaling, but I am working with similarity matrices, not dissimilarities. The question may end up being resolved simply. Here is a bit of substantive