size.equiv.prop.ps {statpsych}

Sample size for a paired-samples proportion equivalence test

Description

Computes the sample size required to perform an equivalence test for the difference in population proportions with desired power in a paired-samples design. The value of h specifies a range of practical equivalence, -h to h, for the difference in population proportions. The absolute difference in the proportion planning values must be less than h. Equivalence tests often require a very large sample size. Equivalence tests usually use 2 x alpha rather than alpha (e.g., use alpha = .10 rather alpha = .05). 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.equiv.prop.ps(alpha, pow, p1, p2, phi, h)

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

upper limit for range of practical equivalence

Value

Returns the required sample size

Examples

size.equiv.prop.ps(.1, .8, .30, .35, .40, .15)

# Should return:
# Sample size
#         173