Non-response in establishment surveys is a very important problem that can bias results of statistical analysis. The bias can be considerable when the survey data is used to do multivariate analysis that involve several variables with different response rates, which can reduce the effective sample size considerably. Fixing the non-response, however, could potentially cause other econometric pro...

OBJECTIVES The aim of this paper is to examine the costs of introducing a nursing-led ward program together with examining the impact this may have on patients' outcomes. METHODS The study had a sample size of 177 patients with a mean age of 77, and randomized to either a treatment group (care on a nursing-led ward, n = 97) or a control group (standard care usually on a consultant-led acute w...

Motivated by an example in nutritional epidemiology, we investigate some design and analysis aspects of linear measurement error models with missing surrogate data. The specific problem investigated consists of an initial large sample in which the response (a food frequency questionnaire, FFQ) is observed and then a smaller calibration study in which replicates of the error prone predictor are ...

With nonnormal data, the typical confidence interval of the correlation (Fisher z') may be inaccurate. The literature has been unclear as to which of several alternative methods should be used instead, and how extreme a violation of normality is needed to justify an alternative. Through Monte Carlo simulation, 11 confidence interval methods were compared, including Fisher z', two Spearman rank-...

Clustering in RCTs occurs when participants or units are allocated to an intervention in a group rather than independently or when multiple measurements are taken from the same individual. Cluster RCTs occur frequently in clinical orthodontic research; however, only a quarter of published trials take account of the effects of clustering in the design and analysis of these trials. The effects of...

This article summarizes results of 7S studies that reported accuracy for males and females at decoding nonverbal communication. The following attributes of the studies were coded: year, sample size, age of judges, sex of stimulus person(s), age of stimulus person(s), and the medium and channel of communication (e.g., photos of facial expressions, filtered speech). These attributes were examined...

In studies of morphology, methods for comparing amounts of variability are often important. Three different ways of utilizing determinants of covariance matrices for testing for surplus variability in a hypothesis sample compared to a reference sample are presented: an F-test based on standardized generalized variances, a parametric bootstrap based on draws on Wishart matrices, and a nonparamet...