4. If Juan completes his part on time, the probability that Jacob completes on time is .9, but if Juan is late, the probability that Jacob completes on time is only .7.

Use simulation (with at least 20 trials) to estimate the probability that the project is completed on time.

Think carefully about this one. For example, you might use a random digit to represent each part of the project (four in all). For the first digit (Maria’s part), 1–8 could represent on time and 9 and 0 could represent late. Depending on what happened with Maria (late or on time), you would then look at the digit representing Alex’s part. If Maria was on time, 1–9 would represent on time for Alex, but if Maria was late, only 1–6 would represent on time. The parts for Juan and Jacob could be handled similarly.

6.85 In Exercise 6.84, the probability that Maria completes her part on time was .8. Suppose that this probability is really only .6. Use simulation (with at least 20 trials) to estimate the probability that the project is completed on time.