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.
For more details, see Section 1.19 of Bonett (2021, Volume 4)
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
References
Bonett DG (2021).
Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.
Examples
size.ci.indirect(.05, .4, .5, .2)
#> Sample size
#> 106
# Should return:
# Sample size
# 106