Find the indicated probabilities by referring to the tree diagram below.
Suppose there are two bags. Bag 1 contains 8 white balls and 4 black balls. Bag 2 contains 4 white balls and 4 black balls. Select a bag at random, and then draw a ball.

a.) What is the probability that a white ball is chosen? Answer 1 Question 1
(round your answer to 3 decimal places

b.) Given that a white ball is chosen, what is the probability that it came from Bag 2? Answer 2 Question 1
(round your answer to 3 decimal places)