Mediation Analysis Confidence Intervals
We provide functions to compute confidence intervals (CIs) for a well–defined nonlinear function of the model parameters (e.g., product of k coefficients) in single–level and multilevel structural equation models.
| Package: | RMediation |
| Type: | Package |
| Version: | 1.1.4 |
| Date: | 2016-3-12 |
| License: | GPL-2 |
| LazyLoad: | yes |
medci produces a CI for the product of two normal random variables using three methods: the distribution of the product of coefficients, Monte Carlo, and asymptotic normal theory with the multivariate-delta standard error (Asymptotic-Delta) method.
pprodnormal produces percentiles for the distribution of product of two normal random variables.
qprodnormal generates quantiles for the distribution of product of two normal random variables.
ci produces a CI for a well–defined nonlinear function of the model parameters in single–level and multilevel structural equation models using the Monte Carlo and Asymptotic-Delta method.
Two web applications of the RMediation program are available from http://amp.gatech.edu/RMediation and http://amp.gatech.edu/MonteCarlo.
Davood Tofighi dtofighi@unm.edu and David P. MacKinnon davidpm@asu.edu
Maintainer: Davood Tofighi <dtofighi@unm.edu>
MacKinnon, D. P., Fritz, M. S., Williams, J., and Lockwood, C. M. (2007). Distribution of the product confidence limits for the indirect effect: Program PRODCLIN. Behavior Research Methods, 39, 384–389.
Meeker, W. and Escobar, L. (1994). An algorithm to compute the CDF of the product of two normal random variables. Communications in Statistics: Simulation and Computation, 23, 271–280.
Tofighi, D. and MacKinnon, D. P. (2011). RMediation: An R package for mediation analysis confidence intervals. Behavior Research Methods, 43, 692–700. doi:10.3758/s13428-011-0076-x
Tofighi, D., and MacKinnon, D. P. (2016). Monte Carlo confidence intervals for complex functions of indirect effects. Structural Equation Modeling: A Multidisciplinary Journal, 23, 194-205. http://doi.org/10.1080/10705511.2015.1057284
medci(mu.x=.2,mu.y=.4,se.x=.1,se.y=.05,rho=0,alpha=.05) pprodnormal(q=.4, mu.x=.5, mu.y=.3, se.x=.03, se.y=.08, rho= 0) qprodnormal(p=.1, mu.x=.5, mu.y=.3, se.x=.03, se.y=.8, rho=0) ci(mu=c(b1=0,b2=0),Sigma=c(1,2,10), quant=~b1*b2) ci(mu=c(b1=1,b2=.7,b3=.6, b4= .45), Sigma=c(.05,0,0,0,.05,0,0, .03, 0, .03), quant=~b1*b2*b3*b4, type="all", plot=TRUE, plotCI=TRUE)
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