Dear Michael, >From ?effect (under "Warnings and Limitations"):
"Binomial generalized linear models cannot have a matrix of successes and failures on the left-hand side of the model formula; instead specify the proportion of successes (i.e., successes/(successes + failures)) as the response, and give the number of binomial trials (i.e., successes + failures) in the weights argument to glm." Best, John ------------------------------------------------ John Fox Sen. William McMaster Prof. of Social Statistics Department of Sociology McMaster University Hamilton, Ontario, Canada http://socserv.mcmaster.ca/jfox/ On Wed, 11 Apr 2012 07:20:51 -0400 Michael Kubovy <kub...@virginia.edu> wrote: > > sessionInfo() > R version 2.15.0 (2012-03-30) > Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit) > > locale: > [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8 > > attached base packages: > [1] grid datasets splines utils stats > [6] graphics grDevices methods base > > other attached packages: > [1] effects_2.1-0 colorspace_1.1-1 > [3] nnet_7.3-1 nlme_3.1-103 > [5] lattice_0.20-6 reshape_0.8.4 > [7] plyr_1.7.1 catdata_1.0 > [9] cacheSweave_0.6-1 stashR_0.3-5 > [11] filehash_2.2-1 BiocInstaller_1.4.3 > [13] ctv_0.7-4 sos_1.3-1 > [15] brew_1.0-6 Hmisc_3.9-3 > [17] survival_2.36-12 MASS_7.3-17 > > loaded via a namespace (and not attached): > [1] cluster_1.14.2 digest_0.5.2 tools_2.15.0 > > # copy and paste the following: > library( catdata ) > data( unemployment ) > unempt <- unemployment > unempt$durbin <- unempt$durbin - 1 > library( reshape ) > unempt <- melt( table( unempt ) ) > unempw <- cast( unempt, age ~ durbin ) > names( unempw ) <- c( 'age', 'short', 'long' ) > modt <- glm( durbin ~ age, weights = value, family = binomial, data = unempt ) > modw <- glm( cbind( short, long ) ~ age, family = binomial, data = unempw ) > library( effects ) > modt.ef <- effect( 'age', modt ) # works! > modw.ef <- effect( 'age', modw ) # doesn't work! > # Error in eval(expr, envir, enclos) : object 'age' not found > # end > > ______________________________________________ > Professor Michael Kubovy > University of Virginia > Department of Psychology > for mail add: for FedEx or UPS add: > P.O.Box 400400 Gilmer Hall, Room 102 > Charlottesville, VA 22904-4400 485 McCormick Road > USA Charlottesville, VA > 22903 > room phone > Office: B011 +1-434-982-4729 > Lab: B019 +1-434-982-4751 > WWW: http://www.people.virginia.edu/~mk9y/ > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.