similar to: cross-validation / sensitivity anaylsis for logistic regression model

Greetings: As I am not a windows user, I cannot try this: is it possible to install rgdal on windows without having to compile it from source ? Compilation on MacOS is within my abilities, however each time i try and install the rgdal package it dies complaining that it cannot find gdal-config --- which was recently installed with GRASS. I have updated my PATH environment variable, logged

Greetings, Experimenting with the cluster package, and am starting to scratch my head in regards to the *best* way to standardize my data. Both functions can pre-standardize columns in a dataframe. according to the manual: Measurements are standardized for each variable (column), by subtracting the variable's mean value and dividing by the variable's mean absolute deviation. This

Hello: I would like to superimpose vector polygons (state outlines) from a Shape file on top of a satellite image, imported into a SpatialGridDataFrame from GEOTIFF via gdal_translate and readGDAL. When I plot polygon and point shape files in R, into SpatialPointDataFrame and SpatialPolygonDataFrame, the two feature sets line up geographically, so it seems logical that a SpatialGridDataFrame

Is there a function that calculates the inter-rater agreement index (kappa) in R? Thanks ../Murli [[alternative HTML version deleted]]

Hi everyone, Suppose I have a count the occurrences of positive results, and the total number of occurrences: pos <- 14 total <- 15 testing that the proportion of positive occurrences is greater than 0.5 gives a p-value and confidence interval: prop.test( pos, total, p=0.5, alternative='greater') 1-sample proportions test with continuity correction data: 14 out of

Getting a very strange error with a new install of R from source on x86; make[3]: Leaving directory `/tmp/R.INSTALL.r20887/cluster/src' ** R ** data ** moving datasets to lazyload DB Error in factor(c(1, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1), : invalid labels; length 2 should be 1 or 1 Execution halted ERROR: lazydata failed for package 'cluster' ** Removing

Greetings, I am trying to add an extra labled axis in position 3 (top x-axis), with numbers that do not match up with the existing axes. Surely this must be possible, and I am just doing it incorectly. So far I have tried the following: #make a plot plot(TIK, type="l", cex=.25, xlim=c(2,32), ylim=c(0,1600)) #try and add a new axis with different numbers in position 3

Greetings, I have had good success using the clara() function to perform a simple cluster analysis on a large dataset (1 million+ records with 9 variables). Since the clara function is a wrapper to pam(), which will accept known medoid data - I am wondering if this too is possible with clara() ... The documentation does not suggest that this is possible. Essentially I am trying to

Greetings: are there any simple ways to convert an sp class object to a splancs ppp class object, outside of reading the coordinates and computing a bounding box? cheers, -- Dylan Beaudette Soils and Biogeochemistry Graduate Group University of California at Davis 530.754.7341

Greetings, I am using both the lrm() {Design} and glm( , family=binomial()) to perform a a logisitic regression in R. Apart from the typical summary() methods, what other methods of diagnosing logistic regression models does R provide? i.e. plotting an 'lm' object, etc. Secondly, is there any facility to calculate the R^{2)_{L} as suggested by Menard in "Applied Logistic

This may sound like a very naive question, but... give two lists of coordinate pairs (x,y - Cartesian space) is there any simple way to compute the affine transformation matrix in R. I have a set of data which is offset from where i know it should be. I have coordinates of the current data, and matching coordinates of where the data should be. I need to compute the composition of the affine

Greetings, A couple general questions regarding the use of splines to interpolate depth profile data. Here is an example of a set of depths, with associated attributes for a given soil profile, along with a function for calculating midpoints from a set of soil horizon boundaries: #calculate midpoints: mid <- function(x) { for( i in 1:length(x)) { if( i > 1) { a[i] = (x[i] -

Greetings, After pouring over the documentation for the 'colorspace' package, I have not been able to figure out how the plot() method converts colorspace coordinates to RGB values for display on the screen. I am convert between colorspaces with the various as() methods... but cannot seem to find a way to extract RGB (i.e. for displaying on a computer screen) triplets from color space

Hello R-help, I am a recent convert to R from SAS and I am having some difficulty with output of a for loop into a matrix. I have searched the help manuals and the archives, but I can't get my code to work. It is probably a syntax error that I am not spotting. I am trying to make a distance matrix by extracting the distances from each point to all others in a vector (the for loop). I can

I've been asked in private, (and am replying BCC to the asker), >> I saw your post on the R-help archives page about the possibility of >> porting a function from S-Plus called peaks() to R. I am looking for >> some way to locate peaks in a simple x,y data set, and thought that R >> might be the way to go. "of course" it is the way to go, don't get

Dear all: I have a shapefile in UTM coordinate system and I would like to transform it to Lat/Log coordinates (WSG84). The package PBSmapping contains function convUL to transform between the two coordinate systems when data is in the form of a data frame with attributes specifying the coordinate system. However, when shapefiles are imported using function read.shape (package maptools), a list

Hi, I have been trying to use the new .parallel argument with the most recent version of plyr [1] to speed up some tasks. I can run the example in the NEWS file [1], and it seems to be working correctly. However, R will only use a single core when I try to apply this same approach with ddply(). 1. http://cran.r-project.org/web/packages/plyr/NEWS Watching my CPUs I see that in both cases

Hi, Is anyone on the list familiar with an R implementation of Piper Diagrams? Example: http://faculty.uml.edu/nelson_eby/89.315/IMAGES/Figure%209-78.jpg I am thinking that two calls to triax.plot (plotrix) along with some kind of affine-transformed standard plot would do the trick. Not so sure about the final layout, or a nice generalized version for something like lattice. Cheers, Dylan

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Hi, I am trying to use quantile regression to perform weighted-comparisons of the median across groups. This works most of the time, however I am seeing some odd output in summary(rq()): Call: rq(formula = sand ~ method, tau = 0.5, data = x, weights = area_fraction) Coefficients: Value Std. Error t value Pr(>|t|) (Intercept) 45.44262 3.64706 12.46007