pois.conf.int {epitools} | R Documentation |
Calculates confidence intervals for Poisson counts or rates
pois.exact(x, pt = 1, conf.level = 0.95) pois.byar(x, pt = 1, conf.level = 0.95) pois.approx(x, pt = 1, conf.level = 0.95)
x |
count or vector of counts |
pt |
person-time at risk (default = 1) or vector of person-times |
conf.level |
confidence level (default = 0.95) |
By default, pois.exact
calculates an exact confidence interval
for a Poisson count x
(pt = 1
). To calculate an exact
confidence interval for a crude rate (count divided by person-time at
risk), set pt
equal to the person-time at risk. Both x
and pt
can be either a number or a vector of numbers.
By default, pois.byar
calculates a confidence interval for a
Poisson count x
(pt = 1
) using Byar's formula which
approximates the exact method. To calculate a confidence interval for
a crude rate (count divided by person-time at risk), set pt
equal
to the person-time at risk. Both x
and pt
can be either
a number or a vector of numbers (Rothman).
By default, pois.approx
calculates an confidence interval for a
Poisson count x
(pt = 1
) using a normal
approximation to the Poisson distribution. To calculate a confidence
interval for a crude rate (count divided by person-time at risk), set
pt
equal to the person-time at risk. Both x
and
pt
can be either a number or a vector of numbers.
This function returns a n x 6 matrix with the following colnames:
x |
Poisson count |
pt |
person-time at risk |
rate |
crude rate = x/pt |
conf.level |
confidence level |
lci |
lower confidence interval limit |
uci |
upper confidence interval limit |
Visit http://www.epitools.net for the latest.
Tomas Aragon, aragon@berkeley.edu, http://www.medepi.net/aragon; with contributions by Francis Dimzon fdimzon@yahoo.com
Tomas Aragon, et al. Applied Epidemiology Using R. Available at http://www.epitools.net
Kenneth Rothman (2002), Epidemiology: An Introduction, Oxford University Press, 1st Edition.
pois.exact(1:10) pois.byar(1:10) pois.approx(1:10)