JSM 2012 Online Program
The views expressed here are those of the individual authors and not necessarily those of the JSM sponsors, their officers, or their staff.
Online Program HomeActivity Details
|
|
|||
| CE_25C | Tue, 7/31/2012, 8:30 AM - 5:00 PM | HQ-Indigo 202B | |
| Analysis of Overdispersed Data Using SAS — Continuing Education Course | |||
| ASA | |||
| Instructor(s): Jorge Morel, The Procter & Gamble Company, Nagaraj K. Neerchal, University of Maryland Baltimore County | |||
| Overdispersion (extravariation) arises in binomial/multinomial/count data when variances are larger than those allowed by the binomial/multinomial/Poisson model. This phenomenon is caused by clumping, presence of excess of zeros in the data, lack of independence, or clustering. Commonly used overdispersion models include: the Beta-binomial, the Random-clumped Binomial, the Zero-inflated Binomial, the Negative-binomial, the Zero-inflated Poisson and Negative-binomial, the Poisson and Negative-binomial Hurdle models, the Dirichlet-multinomial, and the Random-clumped Multinomial. When covariates are available, the mean and the overdispersion parameters can be modeled using appropriate link functions as in Generalized Linear Models (GLM). Such models will be called Generalized Linear Overdispersion Models (GLOM). GLOM do not always belong to the exponential family, and therefore not usually covered under GLM expositions. The aim of the course is to introduce GLOM using several real-life examples, and illustrate the main methods of estimation such as Quasi-likelihood, Maximum Likelihood and Generalized Estimating Equations. Examples will be analyzed using the SAS® procedures COUNTREG, LOGISTIC, GENMOD, GLIMMIX, NLMIXED and SURVEYLOGISTIC. Basic knowledge of the binomial, Poisson and multinomial distributions is required. Familiarity with logistic and Poisson regressions is recommended. | |||
2012 JSM Online Program Home
For information, contact jsm@amstat.org or phone (888) 231-3473.
If you have questions about the Continuing Education program, please contact the Education Department.