On Jan 7, 2011, at 1:58 PM, kiotoqq wrote:
I have a dataset which looks like this:
cbr dust smoking expo
1 0 0.20 1 5
2 0 0.25 1 4
3 0 0.25 1 8
4 0 0.25 1 4
5 0 0.25 1 4
6 0 0.25 1 8
7 0 0.25 1 8
8 0 0.25 1 4
9 1 0.25 1 8
10 0 0.29 1 7
11 0 0.29 0 7
12 0 0.29 1 7
13 0 0.30 0 10
14 0 0.30 1 10
15
16
.
.
.
How can I compare the risk of getting bronchitis between smoker and
no-smoker?
cbrsmk.tbl <- with(dfrm, table(cbr, smoking) )
cbrsmk.tbl
cbrsmk.tbl[2, ]/(cbrsmk.tbl[1, ]+cbrsmk.tbl[2, ])
(That homework set must be going awfully slowly.)
--
David Winsemius, MD
West Hartford, CT
______________________________________________
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.
