Objectives Many randomised trials use stratified permuted blocks or minimisation to balance key prognostic variables between treatment groups. It is widely argued in the statistical literature that any balancing variables should be adjusted for in the analysis, however a review of major medical journals shows that this is not commonly done. Our objective was to determine the effects of an unadj...

Gauge theory is a theory with constraints and, for that reason, the space of physical states is not a manifold but a stratified space (orbifold) with singularities. The classification of strata for smooth (and generalized) connections is reviewed as well as the formulation of the physical space as the zero set of a momentum map. Several important features of nongeneric strata are discussed and ...

The present study examines how the use of social network sites (SNS) increases the potential of experiencing psychological, reputational and physical vulnerability online. From our theoretical perspective, concerns over the use of social network sites and online vulnerability stem from the ease with which users can amass large and diverse sets of online social connections and the associated mai...

This study investigates the relationships between predictors (i.e., personal traits and mobile activities) of smartphone dependency and its impacts on improper phone use, academic performance and perceived sociability. Using a stratified sampling method, a web survey obtained data from 438 undergraduate smartphone users in Singapore. PLS results show that improper phone use is a critical factor...

Stratified medicine requires identifying predictive markers to determine differential treatment effects for subgroups. Ideally, these markers are then validated in prospective randomised trials. However, many of the methods for the analysis and validation of markers are based on there being a single marker. For example, a biomarker stratified trial design typically stratifies on a single binary...

Much attention has been given to sampling design, and the sampling method chosen directly affects the sampling accuracy. The development of spatial sampling theory has lead to the recognition of the importance of taking spatial dependency into account when sampling. This text uses the new Sandwich Spatial Sampling and Inference (SSSI) software as a tool to compare the relative error, coefficien...

A national web-based survey was administered to 700 undergraduate computer science programs in the United States as part of a stratified random sample of 797 undergraduate computer science programs. The 251 program responses (36% response rate) regarding social and professional issues are presented. This article describes the demographics of the respondents, presents results concerning whether ...

These notes are part of the first chapter of a series of lectures given by the author in the spring of 1970. The ultimate aim of these notes will be to prove the theorem that the set of topologically stable mappings form a dense subset of C∞(N,P ) for any finite dimensional manifolds N and P where N is compact. The first chapter is a study of Thom–Whitney theory of stratified sets and stratifie...