On Fri, 2003-03-28 at 12:49, Meles MELES wrote: > Hi, > somebody asked me to do a Poisson regression on cancer incidence over > years to see wether if there is a descending or an ascending tendancy. > I tried with R, but it complains that the data are not integer but > floating poing data. So, as I never did that sort of thing before, I'm a > bit lost. > > the data serie looks like this > SEX PERIOD INCIDENCE > 1 [1978;1982] 57,3 > 1 [1983;1987] 58,3 > 1 [1988;1992] 65 > 1 [1993;1997] 56,8 > 2 [1978;1982] 4,6 > 2 [1983;1987] 5 > 2 [1988;1992] 5,1 > 2 [1993;1997] 6,2 > > Any suggestions?
You don't have enough information. You need the number of events (y) and the number of person-years at risk (pyar) separately. What you have is the incidence rate (y/pyar) * (some scale factor). With the correct data, your model will look something like this glm(y ~ sex + period + offset(log(pyar)), family=poisson) Judging by the PERIOD variable, I guess that you are looking at cancer incidence data from volumes V to VIII of "Cancer Incidence in Five Continents". In this case it is possible to reconstruce the original age-specific incidence data from the published incidence rate and the population pyramid data. Martyn ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
