Hi Kristy,
I have an ado file that performs probit analysis that had written for a
grad student at my old job. They were doing bioassays for their project
and needed similar information. It was tailored to their specific needs to
make life as easy as possible them.
If you could let me know how your data is set up (i.e. is it collapse into
a table for, or is it one line for every subject in the dataset) I could
easily adapt this program to suit your needs. It performs a probit
analysis and displays the LD50 and associated Feiller confidence
limits. It will also account for natural mortality it that occurs.
James Valcour
At 1/14/03 04:34 PM -0800, you wrote:
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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