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statpsych (version 1.7.0)

size.supinf.prop.ps: Sample size for a paired-samples superiority or inferiority test of proportions

Description

Computes the sample size required to perform a superiority or inferiority test for the difference in population proportions with desired power in a paired-samples design. For a superiority test, specify the upper limit (h) for the range of practical equivalence and specify values of p1 and p2 such that p1 - p2 > h. For an inferiority test, specify the lower limit (-h) for the range of practical equivalence and specify values of p1 and p2 such that p1 - p2 > -h. This function sets the effect size equal to the difference in proportion planning values. Set the phi correlation planning value to the smallest value within a plausible range for a conservatively large sample size.

Usage

size.supinf.prop.ps(alpha, pow, p1, p2, phi, h)

Value

Returns the required sample size

Arguments

alpha

alpha level for hypothesis test

pow

desired power

p1

planning value of proportion for measurement 1

p2

planning value of proportion for measurement 2

phi

planning value of phi correlation

h

lower or upper limit for range of practical equivalence

Examples

Run this code
size.supinf.prop.ps(.05, .9, .35, .20, .45, .05)

# Should return:
# Sample size
#         227


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