The analysis of very small samples of repeated measurements II: A modified Box correction


Skene, SS; Kenward, MG; (2010) The analysis of very small samples of repeated measurements II: A modified Box correction. Statistics in medicine, 29 (27). pp. 2838-2856. ISSN 0277-6715 DOI: https://doi.org/10.1002/sim.4072

Full text not available from this repository. (Request a copy)

Abstract

There is a need for appropriate methods for the analysis of very small samples of continuous repeated measurements. A key feature of such analyses is the role played by the covariance matrix of the repeated observations. When subjects are few it can be difficult to assess the fit of parsimonious structures for this matrix, while the use of an unstructured form may lead to a serious lack of power. The Kenward-Roger adjustment is now widely adopted as a means of providing an appropriate inferences in small samples, but does not perform adequately in very small samples. Adjusted tests based on the empirical sandwich estimator can be constructed that have good nominal properties, but are seriously underpowered. Further, when such data are incomplete, or unbalanced, or non-saturated mean models are used, exact distributional results do not exist that justify analyses with any sample size. In this paper, a modification of Box's correction applied to a linear model-based F-statistic is developed for such small sample settings and is shown to have both the required nominal properties and acceptable power across a range of settings for repeated measurements. Copyright (C) 2010 John Wiley & Sons, Ltd.

Item Type: Article
Keywords: ANOVA, Box correction, covariance matrix, linear model, repeated, measures, Scheffe's method, small samples, RESTRICTED MAXIMUM-LIKELIHOOD, ORTHOGONAL BLOCK STRUCTURE, RANDOMIZED, EXPERIMENTS, VARIANCE, ESTIMATOR
Faculty and Department: Faculty of Epidemiology and Population Health > Dept of Medical Statistics
PubMed ID: 20860066
Web of Science ID: 284206400007
URI: http://researchonline.lshtm.ac.uk/id/eprint/1951

Statistics


Download activity - last 12 months
Downloads since deposit
0Downloads
288Hits
Accesses by country - last 12 months
Accesses by referrer - last 12 months
Impact and interest
Additional statistics for this record are available via IRStats2

Actions (login required)

Edit Item Edit Item