Question

An unfair coin with Pr[H]= 0.4 is flipped. If the. flip results in a head, a marble I selected at. random from an urn containing a four red and six blue marbles. Otherwise, a marble is selected from a different urn containing one red and seven blue marbles.

If selected marble selected is red, what is the probability that the flip resulted in a head?

Answer 1

Here we are using Bayes rule for probability. Since the event of getting a red ball can be in two different cases which are exhaustive. So to find the probability of getting head when we have already got red marble can be computed using Bayes rule . Computation part is as follows.