search for: mikewhit

...alise the results on a 3D scatter plot using the rgl library. However, is there an R function that will fit the new data to the class assignments derived from PCA? I think this is similar to what the SIMCA algoirthm does. Thanks Mike ----- Original Message ----- From: "Mike White" <mikewhite.diu at tiscali.co.uk> To: <R-help at stat.math.ethz.ch> Sent: Wednesday, October 08, 2003 9:25 AM Subject: Re: [R] SIMCA algorithm implementation > Dear All > Is there a SIMCA (Soft Independent Modelling Class Analogy) implementation > on R or does anyone know if is it possible...

Can anyone please tell me if there is a function to calculate confidence intervals for the results of the quantile function. Some of my data is normally distributed but some is also a squewed distribution or a capped normal distribution. Some of the data sets contain about 700 values whereas others are smaller with about 100-150 values, so I would like to see how the confidence intervals change

I want to plot the cluster trees from the results of hclust() on different datasets, but all with the same distance scale corresponding to the dataset with the largest distance range. However, plclust() does not accept ylim values. Does anyone know of a way around this problem? Mike White

With predict.lda the posterior probabilities only relate to the existing Class definitions. This is fine for Class definitions like gender but it is a problem when new data does not necessarily belong to an existing Class. Is there a classification method that gives posterior probabilities for Class membership and does not assume the new data must belong to one of the existing Classes? A new

I am trying to follow the mclust examples in "MCLUST: Software for Model Based Clustering, Density Estimation and Disriminant Analysis" by Chris Fraley and Adrian Raftery, but I cannot reproduce the density and uncertainty surfaces for the Lansing Woods maples. I am using R 1.8.1 with the code below. The same code works fine in S-Plus 6.2 Am I missing something or is this a bug?

I have a training set of data for known classes with 5 observations of 12 variables for each class. I want to use this information to classify new data into classes which are known to be different to those in the training set but each new class may contain one or more observations. The distribution of within class distances is expected to be similar for all classes and this is found to be the

I have been using the ellipse function from the car package and the covariance matrix to draw an ellipse around a group of points to show the confidence limits. However, the points are actually represented by 3 variables so rather than plot each pairwise combination of variables in 2D I would like to plot the 'ellipse' in 3D using the djmrgl package. Can anyone offer advice on how I can

I am having difficulty setting different xlim values in the lattice histogram plot function. An example is shown below. I think I need to convert the limits data.frame to a list of paired values but don't know how. Any help would be appreciated. library(lattice) mat <- as.data.frame(matrix(abs(c(rnorm(100), 10*rnorm(100),20*rnorm(100),30*rnorm(100))),ncol=4))

I have been using Tinn-R with R without any problems but when I try to use it with REvolution R I get the following error message when Tinn-R runs the configuration script and gets to the trDDEInstall() function: ## Start DDE trDDEInstall() > trDDEInstall() Error in structure(.External("dotTcl", ..., PACKAGE = "tcltk"), class = "tclObj") : [tcl] invalid command

Hi Does anyone know if there is a function similar to as.numeric that will extract a numeric prefix from a string as in the following examples? x<-c(3, "abc", 5.67, "2.4a", "6a", "6b", "2.4.a", 3, "4.2a") df.x<-data.frame(Code=x) x.str<-levels(df.x[,1]) # required function result 2.40 3.00 4.20 5.67 6.00 NA Thanks Mike White

I want to calculate the probability that a group will include a particular point using the squared Mahalanobis distance to the centroid. I understand that the squared Mahalanobis distance is distributed as chi-squared but that for a small number of random samples from a multivariate normal population the Hotellings T2 (T squared) distribution should be used. I cannot find a function for

I am trying to use Fisher's z' transformation of the Pearson's r but the standard error does not appear to be correct. I have simulated an example using the R code below. The z' data appears to have a reasonably normal distribution but the standard error given by the formula 1/sqrt(N-3) (from http://davidmlane.com/hyperstat/A98696.html) gives a different results than sd(z). Can

Hi I have measured the UV absorbance (abs) of 10 solutions of a substance at known concentrations (conc) and have used a linear model to plot a calibration graph with confidence limits. I now want to predict the concentration of solutions with UV absorbance results given in the new.abs data.frame, however predict.lm only appears to work for new "conc" variables not new "abs"