size.ci.biphi: Sample size for biserial-phi correlation confidence interval

In statpsych: Statistical Methods for Psychologists

Sample size for biserial-phi correlation confidence interval

Description

Computes the sample size required to estimate a biserial-phi correlation with desired confidence interval precision. Set the biserial-phi planning value to the smallest absolute value within a plausible range for a conservatively large sample size. The column variable is assumed to be naturally dichotomous and the row variable is assumed to be artificially dichotomous.

Usage

size.ci.biphi(alpha, p1, p2, cor, w)

Arguments

alpha	alpha level for 1 - alpha confidence
p1	planning value for row 1 marginal proportion
p2	planning value for column 1 marginal proportion
cor	planning value for biserial-phi correlation
w	desired confidence interval width

Value

Returns the required sample size

Examples

size.ci.biphi(.05, .2, .5, .3, .4)

# Should return:
#  Sample size
#          195

statpsych documentation built on April 4, 2025, 3:20 a.m.