[R] Re : Re : descriptive statistics

[William Revelle]

An alternative way of getting summary statistics by a grouping 
variable is to use describe.by in the psych package:

using Jim Lemon's example:

library(psych)
testmat<-data.frame(sample(1:14,50,TRUE),rnorm(50),runif(50))  #make 
up the data
describe.by(test.mat,testmat[1]    #get descriptive statistics






At 8:17 AM -0800 12/13/10, effeesse wrote:
>what am I supposed to put into function(x)? The indicator for extracting the
>subgroups?
>data is the df. cluster={1,...,14}.
>
>This is how I was compiling:
>
>"for (i in 1:14) {
>my.summary<-data$cluster==i c(mean(?),var(?))
>
>summary(var_A~cluster, fun=my.summary,data=data)
>summary(var_B~cluster, fun=my.summary,data=data)
>summary(var_C~cluster, fun=my.summary,data=data)
>summary(var_D~cluster, fun=my.summary,data=data)
>summary(var_E~cluster, fun=my.summary,data=data)
>summary(var_F~cluster, fun=my.summary,data=data)
>summary(var_G~cluster, fun=my.summary,data=data)
>}"
>
>thanks for your patience.
>--
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