Estimating threshold parameter for glm

["Kellie J. Archer, Ph.D." <kjarcher@vcu.edu>]

I'm using glm to estimate the parameters in a dose response model

glm(activity~ace+dia+cpf+dim,data=allpest,family=quasi(link=log,var=mu))

Can anyone tell me how to estimate the threshold parameter in glm
following the methodology of Schwartz et al (1995) JASA 90(431):862-870?



-- 
Kellie J. Archer, Ph.D.
Assistant Professor, Department of Biostatistics
Fellow, Center for the Study of Biological Complexity
Virginia Commonwealth University
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e-mail: kjarcher@vcu.edu
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website: www.people.vcu.edu/~kjarcher