[R] Beginner question: select cases

Peter Wolkerstorfer - CURE
2006-09-25T11:51:11Z

Hello all,

I hope i chose the right list as my question is a beginner-question.

I have a data set with 3 colums  "London", "Rome" and
"Vienna" - the
location is presented through a 1 like this:
London 	Rome 	Vienna	q1
0		0	1		4
0		1	0		2
1		0	0		3
....
....
....

I just want to calculate the means of a variable q1.

I tried following script:

# calculate the mean of all locations
results <- subset(results, subset== 1 )
mean(results$q1)
# calculate the mean of London
results <- subset(results, subset== 1 , select=c(London))
mean(results$q1)
# calculate the mean of Rome
results <- subset(results, subset== 1 , select=c(Rome))
mean(results$q1)
# calcualate the mean of Vienna
results <- subset(results, subset== 1 , select=c(Vienna))
mean(results$q1)

As all results are 1.68 and there is defenitely a difference in the
three locations I wonder whats going on.
I get confused as the Rcmdr asks me to overwrite things and there is no
"just filter" option.

Any help would be apprechiated. Thank you in advance.

Regards
Peter



___CURE - Center for Usability Research & Engineering___

Peter Wolkerstorfer
Usability Engineer
Hauffgasse 3-5, 1110 Wien, Austria

[Tel]  +43.1.743 54 51.46
[Fax]  +43.1.743 54 51.30

[Mail] wolkerstorfer at cure.at
[Web]  http://www.cure.at