Hi - I am trying to fit sem model with intercepts. Here is what I have in my model.
Exogeneous vars: x1 (continous), x2 (ordinal), x3 (ordinal), x4(continuous)
Endogeneous vars: y1 (continuous), y2 (ordinal), y3 (ordinal)
SEM model:
x1 -> eta1; x2 -> eta1; x3 -> eta2; x4 -> eta2; eta1 -> y1, eta1 -> y2, eta2 -> y2, eta2 -> y3
However, in these arrow models, I don't know how to add intercept onto it. I am trying to find an example code using sem package on how to incorporate intercept but cannot find any documents on the web. Or we can simply add something like this? '1 -> eta1'? This is my first question.
Also, note that since my y2 and y3 are ordinal, I used the 'hetcor' to calculate correlation of observed variables. However, from the document, I would need to use the covariance matrix rather then the correlation. And I need additional column for 1. I am not sure how this matrix should look like and how I can obtain this? If there is any example you could point me to, I would really appreciate. Thank you.
- adschai
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