That depends on what you meant by writing the conditional probability.
Bayes rule says that the probability of testing positive when one has the
disease is calculated as follows:
Pr(T+ | D+)=(Pr(D+ | T+)*Pr(T+))/Pr(D+)
is that what you mean?
Kyle H. Ambert
Department of Behavioral Neuroscience
Oregon Health & Science University
On 8/8/07, sigalit mangut-leiba <[EMAIL PROTECTED]> wrote:
>
> hello,
> i want to do a binomial simulation, by taking 200 var. from one group (x)
> and 300 from another (y).
> the prob. for disease=.6 in both groups.
>
> x <- rbinom(200, 1, .6)
>
> y <- rbinom(300, 1, .6)
> if the person is from group x - the probability to find the disease,
> assuming the person is sick, is .95,
> if he is from group Y its .80.
> i want to know the joint probability: p(the person has the disease and
> tested sick)=P(D+,T+).
> my problem is how to write the conditional prob.
> Thanks for your help, also reference on this subject (binomial simulation)
> would be great.
> Sigalit.
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
[[alternative HTML version deleted]]
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
