On Aug 11, 2010, at 4:53 AM, Dorothea Kirchner wrote:
Hi,
I try to calculate confidence intervals for SMRs using the pois.exact
()-function from the package "epitools". But I have some troubble
with the
NAs. How can I remove the NAs out of my analysis? It doesn't work if
I set the
argument: $CI<-pois.exact($SMR, na.rm = TRUE).
You will need to pre-process your data. The help page for pois.exact
makes no indication that it has an na.rm argument or that it will pass
arguments on to subsequent methods. There are functions for removal of
NA values.
?na.omit
?complete.cases
(Caveat: I am not experienced with the use of this package.) It
appears that pois.exact expects at least two arguments, "x" (=counts)
and "pt" (=person-time), and therefore providing SMR's (= x/pt ) may
not give you desired results. The function will provide a rate as
output although the author appropriately calls it a "crude rate". I am
also puzzled by the use of leading "$"'s in variable names. That is
not a formalism with which I am aware. You didn't provide any sample
data or show what error messages you were getting so it's not possible
to say what other problems may exist.
--
David Winsemius, MD
West Hartford, CT
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