The 2011 ASHS Annual Conference

Objective(s):
A workshop using R and SAS® PROC GLIMMIX with real data examples

The statistical tools available in the agricultural and natural resource sciences have progressed from basic t-tests to ANOVA to Mixed Models and now Generalized Linear Mixed Models. The applications of Generalized Linear Mixed Models (GLMMs) are now available in several statistical software packages. This workshop serves as an introduction to the newly developed GLMMs, focusing on their application in horticulture.  Topics for discussion in the workshop will be:  Review of and defining fixed, random, and mixed models; statistical analysis with non-normal distribution of responses; statistical models with repeated measures; and applicable experimental design covering concepts of power, precision, and sample size.  All topics will be discussed using real data examples from horticulture and related disciplines. The techniques and applications of developing a generalized linear mixed model may be implemented with numerous software packages. This workshop features two: GLMM procedures in R and the GLIMMIX procedure in the SAS software suite. We will provide example code in both packages when possible. The workshop is lecture-based so laptop computers are not necessary for attendance. Participants will be provided a packet of workshop materials prior to the workshop that will include lecture materials and applicable data and code. Participants should bring these materials to the workshop as they will be the materials that the presenters will work from.