search for: willett

I have been working through the book "Applied longitudinal data analysis: modeling change and event occurrence" by Judith D. Singer and John B. Willett. I have been working examples using SAS and also using it as an opportunity for learning to use R for statistical analysis. I ran into some difficulties in chapter 8 which deals with using structural equation modeling. I have tried to use the sem package to replicate the problem solutions in cha...

I am fitting individual growth models using nlme (multilevel models with repeated measurements nested within the individual), and I am trying to calculate the Pseudo R-squared for the models (an overall summary of the total outcome variability explained). Singer and Willett (2003) recommend calculating Pseudo R-squared in multilevel modeling by squaring the sample correlation between observed and predicted values (across the sample for each person on each occasion of measurement). My question is which set of predicted values should I use from nlme in that calculation...

Hi I was asked if lme can use FIML (Full Information Maximum Likelihood) instead of REML or ML but I don't know the answer. Does anybody know if this is implemented in R? Thanks Francisco

I am trying to write the following code in R. The code works in S+ and i am trying to do the program in R. x=discrim(admit~gpa+gmat,prior=c("uniform"),data=data.mm) i wrote the following in R: x=lda(admit~gpa+gmat,data=data.mm) i could not figure out how to write prior=c("uniform") in R. I would get an error every time. I think that it has something to do with

I am trying to model data in which subjects are followed through time to determine if they fall, or do not fall. Some of the subjects fall once, some fall several times. Follow-up time varies from subject to subject. I know how to model time to the first fall (e.g. Cox Proportional Hazards, Kaplan-Meir analyses, etc.) but I am not sure how I can model the data if I include the data for those

I am trying to work my way through the book "Singer, JD and Willett, JB, Applied Longitudinal Data Analysis. Oxford University Press, 2003" using R. I have the SAS code and S-Plus code from the UCLA site (doesn't include chapter 8 or later problems). In chapter 8, there is a structural equation/path model which can be specified for the sem package as fo...

Dear R-help list members I gathered longitudinal data on fish behaviour which I try to analyse using a multi level model for change. Mostly, I am following Singer & Willett (2003), who provide also the S/R code for their examples in the book (e.g. http://www.ats.ucla.edu/stat/Splus/examples/alda/ch4.htm). Of course I am interested in change over time, but I am also very much interested in consistency of behaviour of individuals, that is, does an individual for example...

Hi all, I am just learning R and I am trying to work through the book "Applied Longitudinal Data Analysis" by Singer & Willett. I have some code for this book that supposedly works in S-Plus (I don't have S-Plus so I can't verify that) and I am trying to run the examples in R. Most of the examples run, but I have one plot that gives me an error message. I have provided a small dataset below and the problemat...

Hi R people, i'm looking for the Reciprocal Nearest Neighbour algorithm applied to Ward clustering; I know that it is explained in details in the following book: Downs, G. M.; Willett, P. In Advanced Computer-Assisted Techniques in Drug Discovery; van de Waterbeemd, H., Ed.; VCH: Weinheim, 1994; Vol. 3. but cannot order copies it without knowing the pages involved; could someone communicate the pages or the detailed algorithm ??? Thansk in advance, -- Nicolas Baurin Doctora...

..., DebRoy S, the~R Core~team DS (2007). nlme: Linear and Nonlinear Mixed E_ects Models. R package version 3.1-86, URL http://CRAN.R-project.org. Other books that deal with longitudinal data are: Applied Longitudinal Data Analysis: Modeling Change and Event Occurrence by Judith D. Singer and John B. Willett (social science perspective) and Longitudinal and Panel Data: Analysis and Applications in the Social Sciences by Edward W Frees (a statistician). Both these books have URL's where you can get the R programs for the books. The URL for the Singer and Willet book is: http://www.ats.ucla.edu/stat/...

Dear Wolfgang Viechtbauer and list members: I have discovered your "MiMa" function for fitting meta-analytic mixed-effects models through an earlier discussion on this list. I think it is extremely useful and fills an important gap. In particular, since it is programmed so transparently, it is easy to adapt it for one's own needs. (For example, I have found it easy to identify

Greetings all-- Humble newbie requesting help here. I''ve just installed Ruby 1.8.2, Rake 0.4.15, and RubyGems 0.8.8. When I try to get Rails into place via "gem install rails," I get the error below. What have I done wrong? Can anybody throw me a rope? Attempting local installation of ''rails'' Local gem file not found: rails*.gem Attempting remote

....t...c.s [2002/08/16 15:03:44, 10] lib/util.c:(2926) [050] 00 76 00 01 00 04 80 58 01 00 00 74 01 00 00 00 .v.....X ...t.... -----Original Message----- From: Larry McClellan [mailto:mcclellan@sugar-land.oilfield.slb.com] Sent: Saturday, August 17, 2002 11:41 AM To: Clay Jordan; Jeffrey Willett Subject: Tested Direct Samba extract from Srv252sgl-failure attached Hi Clay, Got your message, and tested a direct extract from SRV252SGL. I'm afraid I gout the usual error. Attached is a screen shot of the UCL command window. I was able to move the same files to the D drive, and ru...