text: question relating to dircrete events? a football crowd contains 50% home supporter, 20% away supporters and 30% who support neither club.  the percentages with a criminal record in each group are 3%, 5% and 4%, respectively.  i)if a supporter is chosen at random, what is the chance s/he will have a criminal record?  (use the law of total probability.) ii)if a supporter is chosen at random and found to have a criminal record, what is the probability s/he is a home supporter? (use bayes theorem and the law of total probability). for every 1000 fans, there are 500 home supporters, 200 away supporters and 300 who support neither club.  3% of the home supporters have a record.  that's 15 people. 5% of the away supporters have a record.  that's 10 people. 4% of the rest have a record.  that's 12 people.  in total, 37 people out of 1000 have a record.  that's 3.7%.  if you pick a person at random and they have a record, the probability that they are a home supporter is 15/37.  that's 41%.