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?
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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