Error Message During ANOVA

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of Rodinsky, Dr Harold R.
Sent: Thursday, March 21, 2013 11:32 AM
To: 'r-help at r-project.org'
Subject: Re: [R] Error Message During ANOVA

I am teaching myself R for use in Psych research. I don't understand
the error message I am getting or how to fix it. Any suggestions will
be greatly appreciated


df1=read.table("fastfood.txt", header=TRUE); df1

c(t(as.matrix(df1)))

r = c(t(as.matrix(df1))) # response data

r

f=c("item1","item2", "item3")

k=3
n=6
tm =gl(k,1, n*k, factor(f))
tm

[1] item1 item2 item3 item1 item2 item3 item1 item2 item3 item1 item2
item3
[13] item1 item2 item3 item1 item2 item3
Levels: item1 item2 item3

av=aov(r~tm)

Error in model.frame.default(formula = r ~ tm, drop.unused.levels =

TRUE) :

   variable lengths differ (found for 'tm')