“…To specify the model to accommodate unobserved heterogeneity, a continuous or finite mixture model specification is required, and instead of specify the distribution of ðy i jx i Þ, the specification of the distribution of ðy i jx i ; u i Þ is required [36] along with the specification of distributional assumptions regarding the random variable u i , which represents the unobserved heterogeneity. If the random variable u i is assumed to be continuous, then a continuous mixture model is specified, conversely, when u i is assumed to be discrete then a semi-parametric finite mixture model (FMM) is specified [35,41]. The finite mixture approach has been used by Deb and Trivedi [35,42] [41] show that estimates of a finite mixture might provide good numerical approximations even when the distribution of u i is continuous; second, provides a natural and intuitively attractive representation of unobserved heterogeneity in a finite, usually small, number of latent classes, each of which may be regarded as a 'type' or 'group [35]'.…”