Figure 1

Structure of a hierarchical model. The replicates j of the generic subject i are normally distributed around a mean value μ _i with a within sample variance σ², i.e. x _ij ~N(μ _i , σ²). The mean values μ _i are normally distributed around a "population" mean value M with between sample variance τ², i.e. μ _i ~N(M, τ²).