HOMEWORK SOLUTIONS FOR MATH 5651 HOMEWORK FOR WEEK 7 OF FALL 2011 Summary: HOMEWORK SOLUTIONS FOR MATH 5651 HOMEWORK FOR WEEK 7 OF FALL 2011 Assignment from fourth edition of DeGroot and Schervish: §3.6:2,4,8,10; §3.7:1,4,7; §3.8:2,3,8; §3.9:2,4,6,8 Sometimes I write P instead of Pr because it's shorter. Problem 2 of §3.6 (a) (Probability to be a junior)= (0.04 + 0.20 + 0.90) (sum the junior row). (Probability to be a junior and never visited museum)= 0.04. (Probability to have never visited a museum given that one is a junior) = (0.04)/(0.04 + 0.20 + 0.90) = .1212 (b) We don't have data on students who have visited three or more times. Best we can do is to calculate the probability that the student is a senior given that she has visited a museum more than once. (Probability that a student has visited more than once)= 0.04+0.04+0.09+0.10. (sum the more-than-once column) (Probability that a senior has visited more than once)= 0.10. (Probability to be a senior given having visited a museum more than once) Collections: Mathematics