table(tmod$groups$g)
For example:
> data[sample(1:1000, size=20),] <- NA
> tmod <- lme(y~x,random=~1|g,data=data, na.action=na.omit)
> table(tmod$groups$g)
1 2 3 4 5 6 7 8 9 10
98 98 99 99 97 96 97 99 98 99
Fletcher, Thomas wrote:
S News List –
I am aware of how to extract the coefficients by group for a linear
mixed effects model (e.g., coef (/lme.model/), but I can’t quite figure
out how to get the sample size for each group. Any suggestions?
To give an example, suppose you have a dataset with 1000 individuals
belonging to one of 10 groups. You create a lme model.
# create data
x <- rnorm(1000)
y <- .5*x+rnorm(1000)
g <- rep(1:10,100)
data <- cbind(x,y,g)
data <- data.frame(data)
#create a linear mixed effects model
tmod <- lme(y~x,random=~1|g,data=data)
# extracts coefficients for each group
coef(tmod)
# How do you get the sample size per group? In this example, the sample
size is balanced by design, but what about real data where the group
sizes are not balanced?
Thanks
Tom
-------------------------------------------------
Thomas D. Fletcher, PhD
Assistant Professor
Department of Psychology
University of Missouri - St. Louis
One University Boulevard
St. Louis, MO 63121
FletcherT@umsl.edu <mailto:FletcherT@umsl.edu>
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NDRI, Inc.
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