Allows user to open and close certain paths.
setupPrepPaths(paths, varLabels, ctrlOpts)
lavaan
-style syntax containing paths with which
to begin model estimation (optional). That is, Y~X indicates that Y
is regressed on X, or X predicts Y. If no header is used,
then variables should be referred to with V followed (with no separation)
by the column number. If a header is used, variables should be referred to using
variable names. To reference lag variables, "lag" should be added to the
end of the variable name with no separation. Defaults to NULL.