search for: jawegelin

...5.0 year 2002 month 04 day 29 language R Thanks for any advice Jake Jacob A. Wegelin, Ph.D. Adjunct Assistant Professor Epidemiology and Preventive Medicine, Univ. California One Shields Ave, TB-168 Davis CA 95616-8638 USA TEL 530.752.2793 FAX 530.752.3239 http://wegelin.ucdavis.edu/ jawegelin at ucdavis.edu

Is there any documentation on what kind of SPSS file can and cannot be read by read.spss? Alternatively, how can one modify or "clean" an SPSS file to make it readable by read.spss? What properties must a *.sav file before read.spss can read it? The file in this example is 270KB, with 5 rows and 173 columns. I have no trouble reading larger files with read.spss, so it's not

..."]), 1,1)) row.names(DAT)<-paste( DAT[,"id"], DAT[,"time"], sep=".") Jacob A. Wegelin Assistant Professor Division of Biostatistics, School of Medicine University of California, Davis One Shields Ave, TB-168 Davis CA 95616-8638 USA http://wegelin.ucdavis.edu/ jawegelin at ucdavis.edu

Alternate title: How can I persuade my students that R is for them? Alternate title: Can R replace SAS, SPSS or Stata for clinicians? I am teaching introductory statistics to twelve physicians and two veterinarians who have enrolled in a Mentored Clinical Research Training Program. My course is the first in a sequence of three. We (the instructors of this sequence) chose to teach R rather than

...han Baron, Professor of Psychology, University of Pennsylvania | Home page: http://www.sas.upenn.edu/~baron | R search page: http://finzi.psych.upenn.edu/ | | | | ------------------------------ | | Message: 32 | Date: Mon, 12 Jul 2004 00:50:58 -0700 (PDT) | From: Jacob Wegelin <jawegelin at ucdavis.edu> | Subject: [R] lme unequal random-effects variances varIdent pdMat | Pinheiro Bates nlme | To: r-help at stat.math.ethz.ch | Message-ID: <Pine.OSX.4.53.0407101928480.2644 at biostat5.ucdavis.edu> | Content-Type: TEXT/PLAIN; charset=US-ASCII | | | How does one implement a li...

help.search("groupedData") says that it's part of the lme4 package, but it appears not to be there (details below). Is this because lme4 is new and (perhaps) still under development? > update.packages() trying URL `http://cran.r-project.org/bin/windows/contrib/1.9/PACKAGES' Content type `text/plain; charset=iso-8859-1' length 19113 bytes opened URL downloaded 18Kb >

If you apply the "max" function to a vector of class "difftime" with units="days", the returned value is in units of "seconds". Is this not a bug? At any rate it can lead to confusing results if one buries a call to "max" deep in some data analysis code. Details: > y<-structure(1, class = "difftime", units = "days")

Often in practical situations a predictor has missing values, so that poly crashes. For instance: > x<-1:10 > y<- x - 3 * x^2 + rnorm(10)/3 > x[3]<-NA > lm( y ~ poly(x,2) ) Error in poly(x, 2) : missing values are not allowed in 'poly' > > lm( y ~ poly(x,2) , subset=!is.na(x)) # This does not help?!? Error in poly(x, 2) : missing values are not allowed in

Here is an answer to a 1999 post. I didn't find a direct answer anywhere on the Web, perhaps because it is "obvious" once one sees it. Suppose you have data from a longitudinal study, where each subject was measured *up to* four times, with missing measurements, so that the data look like this: > MAT<- structure(c(23, 24, 6, 19, 16, 20, 13, 11, NA, 8, NA, 21, 19, 15, 11,

With the current version (rw1070), every time I start R it loads a whole bunch of packages, many of which I do not need in a typical session: > search() [1] ".GlobalEnv" "package:methods" "package:ctest" "package:mva" [5] "package:modreg" "package:nls" "package:ts" "Autoloads" [9]

The as.matrix function behaves in a puzzling manner. The help file says: "`as.matrix' is a generic function. The method for data frames will convert any non-numeric column into a character vector using `format' and so return a character matrix." But this does not appear to be the case in the following example. Instead, as.matrix turns a data.frame into a list, not a

The print method for lme *prints out* the fitted correlation matrix for the random effects. Is there any way to get these values as an object in R? I have examined the components of the lme object (called "junk" in the example below) and the components of summary(junk) without finding these numbers. (How I did this: I dumped the entire lme object to a text file and then used egrep to

Sometimes one might like to obtain pointwise bootstrap bias-corrected, accelerated (BCA) confidence intervals for a large number of statistics computed from a single dataset. For instance, one might like to get (so as to plot graphically) bootstrap confidence bands for the fitted values in a regression model. (Example: Chiu S et al., Early Acceleration of Head Circumference in Children with