st: probit modeling

["Seidel, Kristy" <kristy.seidel@seattlechildrens.org>]

Title: probit modeling

Hello,

Can anyone suggest a reference for how to calculate the confidence limits of an LD50 (i.e. 50% lethal dose level) obtained from a probit model?  The data is from a drug toxicity experiment in mice.  I've figured out how to derive the LD50s from the model parameter estimates, but I'm stuck on how to calculate the variance of the LD50 estimate. 

Thanks,

Kristy
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Kristy Seidel
Clinical Research Center/Research Administration
Children's Hospital and Regional Medical Center,  Seattle WA
kristy.seidel@seattlechildrens.org
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