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bmem (version 2.1)

bmem: Mediation analysis based on bootstrap

Description

Mediation analysis based on bootstrap

Usage

bmem(x, ram, indirect, v, method='tsml', ci='bc', cl=.95, 
     boot=1000, m=10, varphi=.1, st='i', robust=FALSE, 
     max_it=500, moment=FALSE, ...)

Value

The on-screen output includes the parameter estimates, bootstrap standard errors, and CIs.

Arguments

x

A data set

ram

RAM path for the mediaiton model

indirect

A vector of indirect effec

v

Indices of variables used in the mediation model. If omitted, all variables are used.

method

list: listwise deletion, pair: pairwise deletion, mi: multiple imputation, em: EM algorithm.

ci

norm: normal approximation CI, perc: percentile CI, bc: bias-corrected CI, bca: BCa

cl

Confidence level. Can be a vector.

boot

Number of bootstraps

m

Number of imputations

varphi

Percent of data to be downweighted

st

Starting values

robust

Robust method

moment

Select mean structure or covariance analysis. moment=FALSE, covariance analysis. moment=TRUE, mean and covariance analysis.

max_it

Maximum number of iterations in EM

...

Other options for sem function can be used.

Author

Zhiyong Zhang and Lijuan Wang

Details

The indirect effect can be specified using equations such as a*b, a*b+c, and a*b*c+d*e+f. A vector of indirect effects can be used indirect=c('a*b', 'a*b+c').

References

Zhang, Z., & Wang, L. (2013). Methods for mediation analysis with missing data. Psychometrika, 78(1), 154-184.