statpsych (version 2.0.0)

size.equiv.mean.ps: Sample size for a paired-samples mean equivalence test

Description

Computes the sample size required to perform an equivalence test for the difference in population means 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 means. The planning value for the absolute mean difference 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). Set the Pearson correlation value to the smallest value within a plausible range, and set the variance planning value to the largest value within a plausible range for a conservatively large sample size.

For more details, see Section 4.27 of Bonett (2021, Volume 1)

Usage

size.equiv.mean.ps(alpha, pow, var, es, cor, h)

Value

Returns the required sample size

Arguments

alpha

alpha level for hypothesis test

pow

desired power

var

planning value of average variance of the two measurements

es

planning value of mean difference

cor

planning value of the correlation between measurements

h

upper limit for range of practical equivalence

References

Bonett2021statpsych

Examples

size.equiv.mean.ps(.10, .90, 25, .5, .75, 2)

# Should return:
# Sample size
#          49