From: Carlos Mauricio Cardeal Mendes <mcardeal_at_ufba.br>

Date: Wed 26 Oct 2005 - 22:45:14 EST

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Oct 26 23:00:20 2005

Date: Wed 26 Oct 2005 - 22:45:14 EST

Hi everone !

I know its not a epidemiologic or statistic list, but since I´m using R to solve related problems ... here it goes:

This is a code to solve the rate problem, but the real question is:
what´s the correct way to calculate the period rate (3 years period put
together)

The third option is quite different (middle period).
Any suggestions ?

Thanks

Mauricio, Brazil

# Example from Field epidemiology basics computer lab 1

# annual period rates (1989, 1990, 1991)

years <- 1989:1991

deaths <- c(125, 130, 131)

pop <- c(361975, 361401, 366613)

# rates and rates per 10.000 per year

rates <- deaths/pop

ratesf <- round(rates*10000,digits=2)

rates

ratesf

# to calculate the period rate we have 3 possibilities:

# 1) sum of deaths by sum of populations:

rates89_91_1 <- sum(deaths)/sum(pop) rates89_91f_1 <- round(rates89_91_1*10000,digits=2) rates89_91_1 rates89_91f_1

# 2) mean rates:

rates89_91_2 <- (rates[1]+rates[2]+rates[3])/3 rates89_91f_2 <- round(rates89_91_2*10000,digits=2) rates89_91_2 rates89_91f_2

# 3) sum of deahts by middle population (1990):

rates89_91_3 <- (deaths[1]+deaths[2]+deaths[3])/pop[2] rates89_91f_3 <- round(rates89_91_3*10000,digits=2) rates89_91_3 rates89_91f_3 ______________________________________________R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Oct 26 23:00:20 2005

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