Methods Data from 2 separate non-small cell lung cancer clinical trials (TOPICAL and SOCCAR) are used to develop and validate the BB model. Comparisons with Linear, TOBIT, Quantile, Quadratic and CLAD models were carried out. The mean prediction error, R, proportion predicted outside the valid range, clinical interpretation of coefficients, model fit and estimation of Quality Adjusted Life Year...

A discrete-continuous choice model of time allocation to two types of discretionary activities is formulated based on the concept of random utility maximization. The model development takes into account the discreteness inherent in daily activity engagement and time allocation (i.e., one type of activity may not be engaged, therefore no time may be allocated to it at all, during a day). Without...

Biological quantitative data are subjected to censoring when a portion of values cannot be quantified because they are smaller or greater than the limit of detection (LOD) of the laboratory assay. In genetic association studies of quantitative trait, the handling of censored data has received little attention and often the solutions are unsatisfactory. However, the approach used to deal with su...

In this study, we analyze the environmental efficiency performance and its determinants of 29 manufacturing industries in China from 2006 to 2011 by employing a two-stage DEA (data envelopment analysis)-Tobit model. For providing comparative and robust evidence, the 29 manufacturing industries are classified into three groups based on the pollution intensity. In the first stage, a SBM (slacks-b...

We propose a new family of error distributions for model-based quantile regression, which is constructed through a structured mixture of normal distributions. The construction enables fixing specific percentiles of the distribution while, at the same time, allowing for varying mode, skewness and tail behavior. It thus overcomes the severe limitation of the asymmetric Laplace distribution – the ...

Quantitative measurements of environmental factors greatly improve the quality of epidemiologic studies but can pose challenges because of the presence of upper or lower detection limits or interfering compounds, which do not allow for precise measured values. We consider the regression of an environmental measurement (dependent variable) on several covariates (independent variables). Various s...

The health care sector depends to a large extent on human labour. Poor workers’ motivation can greatly affect health outcomes and patient safety. This study examines the influences of motivation on the performance of health care workers using University of llorin Teaching Hospital as case study. 150 questionnaires were administered out which 105 were returned. 59.05% of the workers experienced ...

Parameters of quantitative genetic models have traditionally been estimated by either algebraic manipulation of familial correlations (or familial mean squares), biometric model fitting, or multiple-group covariance structure analysis. With few exceptions, researchers who have used these methods for the analysis of twin data have assumed that their data were multinormal and, consequently, have ...

The standard Tobit maximum likelihood estimator under zero censoring threshold produces inconsistent parameter estimates, when the constant censoring threshold γ is nonzero and unknown. Unfortunately, the recording of a zero rather than the actual censoring threshold value is typical of economic data. Non-trivial minimum purchase prices for most goods, fixed cost for doing business or trading, ...

Amaç: Bu çalışmada Türkiye’de faaliyet gösteren ikinci basamak kamu hastanelerinin teknik etkinliği ortaya konmuştur.Yöntem: Çalışmada Veri Zarflama Analizi (VZA) kullanılmıştır. VZA’dan sonra kurulan Tobit regresyon modeli ile hastanelerin bulunduğu ilin büyükşehir olma durumu, yatak sayısının 200 ve üzerinde devir hızı, doluluk oranı, uzman hekim başına düşen sayısı yardımcı sağlık personeli ...