Over dispersion, Advanced Statistics

Over dispersion is the phenomenon which occurs when empirical variance in the data exceeds the nominal variance under some supposed model. Most often encountered when the modeling data which occurs in the form of proportions or counts, where it is frequently observed that there is more variation than, for instance, an assumed binomial distribution can accommodate.

There might be a variety of relatively easy reasons of the amplified variation, ranging from the presence of one or more outliers, to the mis-specification of model being applied to the data. If none of these explanations could explain the phenomenon then it is likely that it is due to the variation between the response probabilities or correlation between the binary responses, in which case particular modelling procedures might be required. 

 

Posted Date: 7/30/2012 7:48:50 AM | Location : United States







Related Discussions:- Over dispersion, Assignment Help, Ask Question on Over dispersion, Get Answer, Expert's Help, Over dispersion Discussions

Write discussion on Over dispersion
Your posts are moderated
Related Questions
Indirect standardization is the procedure of adjusting the crude mortality or morbidity rate for one or more variables by making use of a known reference population. It may, for in

Least significant difference test is an approach to comparing a set of means which controls the family wise error rate at some specific level, let's assume it to be α. The hypothe

Odds ratio is the ratio of the odds for the binary variable in two groups of the subjects, such as, males and females. If the two possible states of variable are labeled as 'succe

Common cause failures (CCF): Simultaneous failures of the number of components due to a same reason. A reason can be external to the components, or it can be the single failure wh

Multidimensional scaling (MDS)  is a generic term for a class of techniques or methods which attempt to construct a low-dimensional geometrical representation of the proximity matr

Hot deck is a method broadly used in surveys for imputing the missing values. In its easiest form the method includes sampling with replacement m values from the sample respondent

Average age at death : A ?awed statistic summarizing expectancy of the life and other aspects of the mortality. For instance, a study comparing average age at the death for male sy

Morbidity is the term used in the epidemiological studies to describe sickness in the human populations. The WHO Expert Committee on the Health Statistics noted in its sixth repor

The method of displaying the geographical variability of the disease on maps using different colors, shading, etc. The logic is not new, but the arrival of computers and computer g

Genstat: The basic purpose piece of statistical software for the management and the analysis of data. The package incorporates the wide variety of data handling events and a wi