“…If, in addition, σ 2 θ = 0, then the model is equivalent to one in which the trend is fixed, linear and the same for each block. This has been studied by several authors, including Bradley and Yeh [1], Yeh and Bradley [21], Yeh, Bradley and Notz [22], Stufken [20], Lin and Dean [11], Chai and Majumdar [3], Chai [2] and Lin and Stufken [12,13]. Alternatively, if σ 2 θ = ∞, then the model is still equivalent to one in which the trend is fixed and linear, but now possibly different in different blocks.…”