This research is supported by give 1FPRPA0060490100 on the Service out-of Health insurance and Human Attributes, Office regarding Inhabitants Products, from the 2009 Loved ones Believed Research Cooperative Contract.
step 1. Hidden class investigation was a mathematical way of investigating dating for the studies from the distinguishing a set of collectively personal unobserved subgroups one make up the shipments out-of circumstances occurring contained in this a cross-tabulation regarding distinct parameters-here, dating qualities (source: McCutcheon A, Latent Category Data, Beverly Hills, CA: Sage, 1987).