If a woman takes an early pregnancy test, she will either test positive, meaning that the

Suppose that if a woman really is pregnant, there is a 98% chance that she will test

test says she is pregnant, or test negative, meaning that the test says she is not pregnant.

positive. Also, suppose that if a woman really is not pregnant, there is a 99% chance that

she will test negative. Use the probability tree diagram to answer the following questions:

(a) Suppose that 1,000 women take early pregnancy tests and that 100 of them really are

pregnant. What is the probability that a randomly chosen woman from this group will

test positive?

(b) Suppose that 1,000 women take early pregnancy tests and that 50 of then really are

pregnant. What is the probability that a randomly chosen woman from this group will

test positive?