26. Let X;jk' (i, j , k = 0,1, / = 1, . . . , L) denote the entries in a 2 X 2 X 2 X L table with factors A, B, C, and D, and let r _ PABcD,P1BcD,PABcD,P1BcD, i : PA BCD,P1BCD,PABCD,P1BCD, Then (i) under the assumption r, = r there exists a UMP unbiased test of the hypothesis r s ro for any fixed ro; (ii) When / = 2, there exists a UMP unbiased test of the hypothesis rl = r2 -in both cases regardless of whether 0, 1, 2 or 3 of the sets of margins are fixed. Section 9