There are two coins in a basket. One coin has the probability of head 0.5 and for the other coin the probability of head is 0.25. A coin is drawn at random from the basket with equal probability and tossed 5 times.
a) What is the chance of observing 3 heads and 2 tails?
b) Suppose that we have observed 3 heads and 2 tails, what is the probability that the coin we have selected is the unbiased one, i.e. the one in which P(H) = 0.5?