Biometrical Journal

doi: 10.1002/bimj.4710260401pmid: N/A

Gottlieb, R.; Lienert, G. A.; Ludwig, O.; Rockenfeller, K.

doi: 10.1002/bimj.4710260402pmid: N/A

Tables for Bonferroni‐adjusted significance levels of Student's t are provided for r = 3(1)30(5)50 etc. and alphas of 0.05, 0.01 and 0.001. The tables are suggested for various applications, for example in replacing analysis of variance of k samples by r simultaneous t tests. Use of the tables is shown by numerical examples. The adjustment of alpha for improving the efficiency of testing is made by WILKINSON for orthogonal comparisons and by HOLM for nonorthogonal comparisons.

Adam, J.

doi: 10.1002/bimj.4710260404pmid: N/A

Ahrens, H.

doi: 10.1002/bimj.4710260403pmid: N/A

Ramkaran, ; Bhattacharya, Samir K.

doi: 10.1002/bimj.4710260405pmid: N/A

The paper deals with the problem of estimating the mean life θ in an exponential model \documentclass{article}\pagestyle{empty}\begin{document}$f(x/\theta ) = \frac{1}{\theta }e - x/\theta$\end{document}. It is assumed that in addition to the current ordered sample, we have a sample collected sometime in the recent past when the mean life might have been β. We have proposed a Sometimes—Pool procedure which is based on the outcome of a preliminary test of H0: θ=β and obtained the expressions of the bias and MSE. An attempt has been made to locate that region in the parameter space in which the proposed estimator does better (in MSE sense) than the usual estimator based only on the current sample.

Issel, W.

doi: 10.1002/bimj.4710260406pmid: N/A

Lachenbruch, P. A.; Woolson, R. F.

doi: 10.1002/bimj.4710260407pmid: N/A

Two classes of tests for the hypothesis of bivariate symmetry are studied. For paired exponential survival times (t1j, t2j), the classes of tests are those based on t1j‐t2j and those based on log t1j–log t2j. For each class the sign, signed ranks, t and likelihood ratio tests are compared via Pitman's criterion of asymptotic relative efficiency (ARE). For tests based on t1j — t2j, it is found that: (1) the efficacy of the paired t depends on the coefficient of variation (CV) of the pair means, (2) the signed rank test has the same ARE to the sign test as for the usual location problem. For tests based on log t1j — log t2j, the ARE comparisons reduce to the well‐known results for the one‐sample location problem for samples from a logistic density. Hence, the signed rank test is asymptotically efficient. Furthermore, analyses based on log t1j — log t2j are not complicated by the underlying pairing mechanism.

Rasch, D.

doi: 10.1002/bimj.4710260408pmid: N/A

Schemper, M.

doi: 10.1002/bimj.4710260409pmid: N/A

An exact test of KENDALL'S tau is presented, useful in small samples when the asymptotic test may not be adequate. The procedure is proposed especially for situations when ties and/or censored observations are present in the variables to be analyzed by KENDALL'S tau. The paper describes generalizations of the procedure, presents calculated examples and offers a computer program, which facilitates the usage of the proposed procedure.

Goria, M. N.

doi: 10.1002/bimj.4710260410pmid: N/A

Here population measures and their sample analogue for the linear relation between two or more variables are proposed. Two approximations for the measure in the general case are derived and these are then compared with the exact measure in a special case.