size.ci.ratio.prop.ps {statpsych}

Sample size for a paired-samples proportion ratio confidence interval

Description

Computes the sample size required to estimate a ratio of proportions with desired confidence interval precision in a paired-samples design. Set the phi correlation planning value to the smallest value within a plausible range for a conservatively large sample size.

Usage

size.ci.ratio.prop.ps(alpha, p1, p2, phi, r)

Arguments

alpha

alpha level for 1-alpha confidence

p1

planning value of proportion for measurement 1

p2

planning value of proportion for measurement 2

phi

planning value of phi correlation

r

desired upper to lower confidence interval endpoint ratio

Value

Returns the required sample size

Examples

size.ci.ratio.prop.ps(.05, .4, .2, .7, 2)

# Should return:
# Sample size
#          67