| ci.popsize {statpsych} | R Documentation |
Confidence interval for an unknown population size
Description
Computes a Wald confidence interval for an unknown population size using mark-recapture sampling. This method assumes independence of the two samples. This function requires the frequency counts from an incomplete 2 x 2 contingency table for the two samples (f11 is the unknown number of people who were not observed in either sample). This method sets the estimated odds ratio (with .5 added to each cell) to 1 and solves for unobserved cell frequency. An approximate standard error is recovered from the confidence interval.
Usage
ci.popsize(alpha, f00, f01, f10)
Arguments
alpha |
alpha level for 1-alpha confidence |
f00 |
number of people observed in both samples |
f01 |
number of people observed in first sample but not second sample |
f10 |
number of people observed in second sample but not first sample |
Value
Returns a 1-row matrix. The columns are:
Estimate - estimate of the unknown population size
SE - recovered standard error
LL - lower limit of the confidence interval
UL - upper limit of the confidence interval
Examples
ci.popsize(.05, 794, 710, 741)
# Should return:
# Estimate SE LL UL
# 2908 49.49071 2818 3012