In an unbalanced and heteroscedastic one-way random effects model, we compare, by way of simulation, several test statistics for testing the null hypothesis that the variance of the random effects, also named the between group variance, is zero. These tests are the classical F-test, the test...

A control chart procedure has previously been proposed (Champ et al., 1991) for which the Shewhart X ¥ -chart, the cumulative sum chart, and the exponentially weighted moving average chart are special cases. The rapid and easy production of these charts, plus many others, is proposed using...

In time series analysis, the Box-Cox power transformation is generally used for variance stabilization. In this paper we show that the order and the first step ahead forecast of the transformed model are approximately invariant to those of the original model under certain assumptions on the mean...

We use the local influence approach to develop influence measures for identifying observations that strike a disproportionate effect on the maximum likelihood estimate of parameters in models for lifetime data. The proposed method for developing influence measures can be applied to a wide...

Repeating measurements of efficacy variables in clinical trials may be desirable when the measurement may be affected by ambient conditions. When such measurements are repeated at baseline and at the end of therapy, statistical questions relate to: (1) the best summary measurement to use for a...

An expression relating estimation precision in the classical linear model to the number of parameters k and the sample size n is illustrated. A rule of thumb for the sample size is suggested.

This paper presents the calculation of the average outgoing quality limit (AOQL) for the tightened single-level continuous sampling plan (TCSP-1 plan) based on a numerical method. A solution procedure is developed to find the parameters (i, f, k) that will meet the AOQL requirement, while also...

Error measures for the evaluation of forecasts are usually based on the size of the forecast errors. Common measures are, e.g. the mean squared error (MSE), the mean absolute deviation (MAD) or the mean absolute percentage error (MAPE). Alternative measures for the comparison of forecasts are...

A- and D-optimal designs are investigated for a log contrast model suggested by Aitchison & Bacon-Shone for experiments with mixtures. It is proved that when the number of mixture components q is an even integer, A- and D-optimal designs are identical; and when q is an odd integer, A- and...

Several methods for testing the difference between two group means of k independent populations are compared. Simulation shows that the likelihood ratio test with the Bartlett correction factor and the t test with appropriate degrees of freedom perform better, particularly when the sample size...