To update the probability of rain given the observation of cloudiness, you apply Bayes' theorem. You substitute the supplied prior probability of rain, the likelihood of cloudiness given rain, and the marginal probability of cloudiness into the formula.
Conditions: Cloudiness is the observed event (B).; Rain is the event of interest (A).; Prior probabilities and likelihoods are supplied.; P(Cloudiness)>0.
To update the probability of rain given the observation of cloudiness, you apply Bayes' theorem. You substitute the supplied prior probability of rain, the likelihood of cloudiness given rain, and the marginal probability of cloudiness into the formula.
Conditions: Cloudiness is the observed event (B).; Rain is the event of interest (A).; Prior probabilities and likelihoods are supplied.; P(Cloudiness)>0.
The calculation assumes a population of 210 people: 10 librarians and 200 farmers. With 40% of librarians fitting the description (yielding 4 matching librarians) and 10% of farmers fitting it (yielding 20 matching farmers), there are 24 total matches.
Conditions: Population consists only of librarians and farmers with a 1:20 ratio; Likelihoods are stipulated as 40% for librarians and 10% for farmers; Conditioning requires P(E)>0
The calculation assumes a population of 210 people: 10 librarians and 200 farmers. With 40% of librarians fitting the description (yielding 4 matching librarians) and 10% of farmers fitting it (yielding 20 matching farmers), there are 24 total matches.
Conditions: Population consists only of librarians and farmers with a 1:20 ratio; Likelihoods are stipulated as 40% for librarians and 10% for farmers; Conditioning requires P(E)>0