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KDA posted on Thursday, December 29, 2005  10:42 am



Dear Linda and Bengt: I have specified a SEM with the following paths: 1) direct paths from observed variables A, C to observed variable B. 2) In addition to (1) above, I have also specified a path from C to latent construct D, and from D to B. I have two questions I'd like to ask about this model: 1. How do I test the hypothesis that the mean level of B exceeds that of A, controlling for all the paths specified above? 2. Is it correct to compare the direct path from C to B with the product of the paths from C to D and D to B (joint effect) if I am interested in the relative strength of the direct versus mediated path to B? I would greatly appreciate your advice. Thanks! 

bmuthen posted on Thursday, December 29, 2005  6:15 pm



1. Seems like you want to test the intercept for B. 2. Yes, this seems reasonable. 


Dear Linda and Bengt, I have the same question as 1. How does testing the intercept test whether B is higher than A? I understood that the intercept was just the regression intercept unless I missing something. Thanks in advance. 


I was focusing on the phrase "controlling for" in 1., which to me suggests looking at differences conditioning on something. That led me to suggest focusing on the intercept  in line with the ANCOVA answer I gave you. But perhaps I misunderstood, and the individual who asked is more interested in growth matters. 

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