From: Kjetil Brinchmann Halvorsen (kjetil@entelnet.bo)
Date: Wed 01 Jan 2003 - 11:12:50 EST
Message-id: <3E123282.000003.02356@personal-apzxmv>
A better option for a confidence interval for LD50
might be Fiellers method.
To see how to get the numbers from the object returned from dose.p, use for
example
str(object) or names(object).
Kjetil Halvorsen
-------Original Message-------
From: Ngayee J Law
Date: Tuesday, December 31, 2002 7:17:39 PM
To: apjaworski@mmm.com
Cc: r-help@stat.math.ethz.ch
Subject: Re: [R] Probit Analysis
Hi Andy,
Thanks! glm and dose.p can do exaclty what I want to do. Just a quick
question,
how can I extract the numbers in the glm.dose object created by the dose.p?
My
goal is to calculate a 95% CI for the 'LD50'.
- Jacqueline
apjaworski@mm
m.com To: "Ngayee J Law" <Ngayee.Law@celeradiagnostics.com>
cc: r-help@stat.math.ethz.ch
12/31/2002 Subject: Re: [R] Probit Analysis
02:47 PM
Jacqueline,
This should be a simple application of GLM. Check the help pages for glm,
family and dose.p in library MASS. Look at the example at the bottom of
the dose.p help page - it does almost exactly what you need.
Hope this helps,
Andy
__________________________________
Andy Jaworski
Engineering Systems Technology Center
3M Center, 518-1-01
St. Paul, MN 55144-1000
-----
E-mail: apjaworski@mmm.com
Tel: (651) 733-6092
Fax: (651) 736-3122
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| Subject: [R] Probit Analysis
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Hello all,
I have a very simple set of data and I would like to analyze them with
probit analysis.
The data are:
X Event Trial
100 8 8
75 8 8
50 6 8
25 4 8
10 2 8
0 0 8
I want to estimate the value of X that will give a 95% hit rate
(Event/Trial) and the corresponding
95% CI. Anyone can offer some help? Thanks!!
- Jacqueline
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