[R] Probit Analysis: Confidence Interval for the LD50 using Fieller's and Heterogeneity (UNCLASSIFIED)

[David Winsemius]

On Nov 22, 2010, at 2:24 PM, Kenney, Colleen T CTR USA AMC wrote:

> Classification:  UNCLASSIFIED
> Caveats: NONE
>
> A similar question has been posted in the past but never answered.  My
> question is this: for probit analysis, how do you program a 95%
> confidence interval for the LD50 (or LC50, ec50, etc.), including a
> heterogeneity factor as written about in "Probit Analysis" by
> Finney(1971)?  The heterogeneity factor comes into play through the
> chi-squared test for homogeneity and is equal to h=chi^2/(k-2),  
> where k
> is the number of doses and k-2 are the degrees of freedom.
>
> I have done a lot of research on this and really appreciate any help
> anyone can provide.  Thank you!

The reason it may not have had a rely ... assuming the questions was  
homomorphic to this one... is that there is no R content in this  
question. You may want to post on:

http://stats.stackexchange.com/

But I suggest you be somewhat more descriptive than just citing a 40  
year-old text.

-- 

David Winsemius, MD
West Hartford, CT