نتایج جستجو برای: population effects

تعداد نتایج: 2155889  

Journal: :Technometrics 2014
Kalliopi Mylona Peter Goos Bradley A. Jones

Now, we come to offer you the right catalogues of book to open. optimal design of blocked and split plot experiments is one of the literary work in this world in suitable to be reading material. That's not only this book gives reference, but also it will show you the amazing benefits of reading a book. Developing your countless minds is needed; moreover you are kind of people with great curiosi...

2010
Paul Clarke Claire Crawford Fiona Steele Anna Vignoles

The Choice Between Fixed and Random Effects Models: Some Considerations for Educational Research We discuss fixed and random effects models in the context of educational research and set out the assumptions behind the two approaches. To illustrate the issues, we analyse the determinants of pupil achievement in primary school, using data from the Avon Longitudinal Study of Parents and Children. ...

2016
Chunming Xiu Qiaowei He Peng Zou Hongtao Zhang

X-ray cross-complementing group 4 (XRCC4) is crucial for cells to maintain genetic stability thereby inflicting carcinogenesis. To date, epidemiologic findings have reached conflicting and ambiguous conclusions on the role of XRCC4 rs1805377 polymorphism in cancer risks. We made a comprehensive quantitative evaluation by performing a meta-analysis. Eligible publications assessing the associatio...

1998
Mark N. Harris László Mátyás

Gravity type models have often been used to analyse trade flows between countries and trading blocs. Previously however, these models were only applied to either cross-section data, or to single country time-series data, which imposed severe explicit (or implicit) restrictions on the specification of the model. Recently Gravity models have been generalised and adapted to a panel data setting, w...

2009
Christopher J. Boyce

In studies of subjective well-being, economists and other researchers typically use a fixed or random effect estimation to control for unobservable heterogeneity across individuals. Such individual heterogeneity, although substantially reducing the estimated effect of many characteristics, is little understood. This paper shows that personality measures can account for 20% of this heterogeneity...

2010
Paul Clarke Claire Crawford Fiona Steele Anna Vignoles

We discuss the use of fixed and random effects models in the context of educational research and set out the assumptions behind the two modelling approaches. To illustrate the issues that should be considered when choosing between these approaches, we analyse the determinants of pupil achievement in primary school, using data from the Avon Longitudinal Study of Parents and Children. We conclude...

2009
Minjung Kyung Jeff Gill George Casella

An alternative to the classical mixedmodel with normal random effects is to use a Dirichlet process to model the random effects. Such models have proven useful in practice, and we have observed a noticeable variance reduction, in the estimation of the fixed effects, when the Dirichlet process is used instead of the normal. In this paper we formalize this notion, and give a theoretical justifica...

2007
Mark Gersovitz Ann Harrison Larry Katz Daniel Sichel ANNE C. CASE

In this paper I discuss economic processes that may give rise to spatial patterns in data, and explore the relative merits of alternative modeling approaches when data are spatially correlated. Specifically, I present an estimation scheme that allows for spatial random effects, and focus attention on cases in which such a framework may be preferred to the more general fixed effects framework th...

1997
N. Gengler L. D. Van Vleck M. D. MacNeil

Two data sets from the USDA Livestock and Range Research Laboratory were analyzed to study dominance variance and the influence of dominance relationships. The first consisted of 4,155 birth weight (3,884 weaning weight) records of inbred USDA Line 1 Herefords. The second consisted of 8,065 birth weight (7,380 weaning weight) records from a line-cross experiment with five lines. Two models were...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده ریاضی 1390

the main objective in sampling is to select a sample from a population in order to estimate some unknown population parameter, usually a total or a mean of some interesting variable. a simple way to take a sample of size n is to let all the possible samples have the same probability of being selected. this is called simple random sampling and then all units have the same probability of being ch...

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