size.ci.indirect: Sample size for an indirect effect confidence interval

In statpsych: Statistical Methods for Psychologists

Sample size for an indirect effect confidence interval

Description

Computes the approximate sample size required to estimate a population standardized indirect effect in a simple mediation model. The direct effect of the independent (exogenous) variable on the response variable, controlling for the mediator variable, is assumed to be negligible.

Usage

size.ci.indirect(alpha, cor1, cor2, w)

Arguments

alpha	alpha level for 1-alpha confidence
cor1	planning value of correlation between the independent and mediator variables
cor2	planning value of correlation between the mediator and response variables
w	desired confidence interval width

Value

Returns the required sample size

Examples

size.ci.indirect(.05, .4, .5, .2)

# Should return:
# Sample size
#         106
 

statpsych documentation built on June 10, 2025, 5:11 p.m.