You need to derive the expectation of the product of the 3 random slopes to check.
Niki Su posted on Tuesday, December 19, 2017 - 11:37 pm
Thank you very much. But maybe I didn't describe the question clearly. In a 1-1-1 model, the indirect effect should be the product of 2 random slopes plus their covariance. But when it is a 1-1-1-1 model, I don't know how to deal with the covariance. Back to the 1-1-1-1 model described initially, should the indirect effect be the product of the 3 random slopes plus covariances of each two of the 3 random slopes?