Rob, If 'sex' is indeed an exogenous variable (ie. predictor only), you can simply code it as (1=male, 2=female) and use it as a covariate in any sem model. In lavaan, you can explicitly use the argument 'fixed.x=TRUE', which will regard all exogenous covariates as fixed variables. Their means/variances/covariances are not included in the model estimation (so they do not have to be normally distributed), but they are simply set at their sample values. In essence, this is exactly what happens in ordinary regression, when a categorical predictor is recoded as a dummy variable.
Yves. -- View this message in context: http://r.789695.n4.nabble.com/binary-exogenous-variable-in-path-analysis-in-sem-or-lavaan-tp3355987p3401870.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
