Question about probability theory ( please answer in detail so that I can understand it properly, many thanks)

Question

Q) A teenager is mugged for his expensive, size 9, trainers by a white man. A white suspect from the same city is arrested wearing a pair of similar trainers.

There were 200 pairs of these size 9 trainers sold in the city. There are approximately 200,000 white males in the city.

a) Express the posterior odds of the suspect being guilty in terms of the prior odds.

b) If the prior odds are taken to be 1/200,000, what are the posterior odds of guilt?

c) What is the posterior probability of guilt?

Answer 1

This maybe of some help to you

http://plato.stanford.edu/entries/probability-interpret/

Answer 2

How many people are in the city? or How many of the 200 pairs of shoes were sold to white men?

Is it asking for the odds that random person "A" is both a white male and has the shoes, or is it asking that given that the suspect in custody is both a white male and has a pair of trainers, what is the probability that he is guilty?
One is 1/400,000,000 (Random person "A" meets both criteria)
the other is a maximum of 1/200, but you must either establish that all 200 pairs of trainers were sold to white males, or remove the number of pairs of shoes that were sold to a non-white male.
For example, If there are1,000,000 people in the city and all types of people bought the shoes equally, then there are only 40 pairs of shoes belong to white men. That means the the odds of the white male suspect in custody in 1/40.
You might think to remove one pair of shoes from the list as they were stolen, but they get added back in by the culprit himself having a pair.
This again all is assuming only onw pair of shoes was purchased by each person. If one guy bought two pairs of shoes, the odds change.

Answer 3

ok. you let us know what different u . s . has a similar inhabitants as U.ok. and we are able to study them. Or, shall we use the portuguse on a share foundation. a million/6. what ever makes you happy.