Creates model latent variables

        Returns
        ----------
        None (changes model attributes)

def _create_latent_variables(self):
        """ Creates model latent variables

        Returns
        ----------
        None (changes model attributes)
        """

        for parm in range(self.z_no):
            self.latent_variables.add_z('Scale ' + self.X_names[parm], fam.Flat(transform='exp'), fam.Normal(0, 3))
            self.latent_variables.z_list[parm].start = -5.0
        self.z_no = len(self.latent_variables.z_list)