I have a problem of calculating a conditional probability, and want to know
what is the right formula.
Suppose a family consists of two parents and m offsprings. Consider a
disease that affects both genders equally. Given an offspring is affected,
what is the probability that neither two parents nor other m-1 offsprings
are affected. Am I right to use the following formula ?
Pr(F1=0; F2=1) / Pr(F2>0)
where F1 is the number of affections in parents, and F2 is the number of
affections among offsprings.
Thanks,
James.
