نتایج جستجو برای: zero inflated

تعداد نتایج: 153089  

Background: The effective use of limited health care resources is of prime importance. Assessing the length of stay (LOS) is especially important in organizing hospital services and health system. This study was conducted to identify predictors of LOS among patients who were admitted to a general surgical unit.    Methods: In this cross-sectional study, the sample included all patien...

Journal: :Computational Statistics & Data Analysis 2014

2009
Hai Liu Kung-Sik Chan

Zero-inflation problem is very common in ecological studies as well as other areas. Nonparametric regression with zero-inflated data may be studied via the zero-inflated generalized additive model (ZIGAM), which assumes that the zero-inflated responses come from a probabilistic mixture of zero and a regular component whose distribution belongs to the 1-parameter exponential family. With the fur...

Journal: :Brazilian Journal of Probability and Statistics 2012

2016
Elizabeth Dastrup Mills

Semicontinuous data consist of a combination of a point-mass at zero and a positive skewed distribution. This type of non-negative data distribution is found in data from many fields, but presents unique challenges for analysis. Specifically, these data cannot be analyzed using positive distributions, but distributions that are unbounded are also likely a poor fit. Two-part models incorporate b...

2009
HAI LIU

Zero-inflated data abound in ecological studies as well as in other scientific and quantitative fields. Nonparametric regression with zero-inflated response may be studied via the Zero-Inflated Generalized Additive Model (ZIGAM). ZIGAM assumes that the response variable follows a probabilistic mixture distribution of a zero atom and a regular component whose distribution belongs to some 1-param...

2008
Donald Erdman Laura Jackson Arthur Sinko

Real-life count data are frequently characterized by overdispersion and excess zeros. Zero-inflated count models provide a parsimonious yet powerful way to model this type of situation. Such models assume that the data are a mixture of two separate data generation processes: one generates only zeros, and the other is either a Poisson or a negative binomial data-generating process. The result of...

Journal: :Accident; analysis and prevention 2010
Nataliya V Malyshkina Fred L Mannering

In this study, a two-state Markov switching count-data model is proposed as an alternative to zero-inflated models to account for the preponderance of zeros sometimes observed in transportation count data, such as the number of accidents occurring on a roadway segment over some period of time. For this accident-frequency case, zero-inflated models assume the existence of two states: one of the ...

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