Hello,
This is Elaine.
I am trying a path analysis using lavaan Package.
There are three explanatory variables: X, Z, and M.
The response variable is Y.
A, b, and c have direct effects on Y.
On the other hand, X and Z also have direct effects on M.
In other words, X and Z have indirect effects on Y.
I found the code example of lavaan package describes only one indirect
effect as below.
Please kindly advise how to modify it as two indirect effects.
Thank you.
Elaine
> set.seed(1234)
> X <- rnorm(100)
> M <- 0.5*X + rnorm(100)
> Y <- 0.7*M + rnorm(100)
> Data <- data.frame(X = X, Y = Y, M = M)
> model <- ' # direct effect
+ Y ~ c*X
+ # mediator
+ M ~ a*X
+ Y ~ b*M
+ # indirect effect (a*b)
+ ab := a*b
+ # total effect
+ total := c + (a*b)
+ '
> fit <- sem(model, data=Data)
> summary(fit)
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