Confidence interval for a 2-group proportion ratio

Source: R/statpsych3.R

Computes an adjusted Wald confidence interval for a population proportion ratio in a 2-group design.

ci.ratio.prop2(alpha, f1, f2, n1, n2)

Arguments

alpha

alpha level for 1-alpha confidence

f1

number of participants in group 1 who have the attribute

f2

number of participants in group 2 who have the attribute

n1

sample size for group 1

n2

sample size for group 2

Value

Returns a 1-row matrix. The columns are:

  • Estimate - adjusted estimate of proportion ratio

  • LL - lower limit of the adjusted Wald confidence interval

  • UL - upper limit of the adjusted Wald confidence interval

References

Price RM, Bonett DG (2008). “Confidence intervals for a ratio of two independent binomial proportions.” Statistics in Medicine, 27(26), 5497--5508. ISSN 02776715, doi:10.1002/sim.3376 .

Examples

ci.ratio.prop2(.05, 35, 21, 150, 150)
#>  Estimate       LL       UL
#>  1.658824 1.017253 2.705025

# Should return:
# Estimate       LL       UL
# 1.666667 1.017253 2.705025