Dear listers,
I am writing to ask a few questions regarding the calculation of total effect = direct effect + indirect effect.
Suppose I am interested in the relationship between X and Y and Z. I also have demographic variables to consider such age and sex.
1) My first question is,
If I want to calculate the total effect of X on Y, do I have to control for Age and Sex or not?
In other words, is Rxy the total effect or Rxy.age,sex the total effect?
2) My second question is,
As far as I know, the SEM package softwares (e.g. Lisrel or Amos) automatically calculate the direct and indirect effect of included components.
Unfortunately, I now do not use such softwares but just SPSS, and need to calculate the total, direct and indirect effect between X Z and Y.
Then, is there anyway to test the significance of indirect effect of path coefficients a*b (which are multiplied indirect effects of the path from X to Z(a) and Z to Y(b)?
Thank you very much for your attention and help in advance and sorry if these are too basic questions to look at.
I will appreciate it much more if you can suggest any reading materials to grasp these topics more clearly.
Regards,
Mike
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