13. a) What is the probability of an event that is certain to occur? b) What is the probability of an impossible event? c) On a true/false problem, what is the probability of answering a question correctly if you make a random guess? d) On a multiple-choice test with five possible answers for each question, what is the probability of answering a question correctly if you make a random guess? 14. Two thousand raffle tickets are sold at a church raffle for $1 each. There are three prizes offered: $500, $250 and $100. What is the expected value of your winnings if you buy 1 ticket? 15. In a research poll, respondents were asked how a fruitcake should be used. Use Number of respondents, f Doorstop 50 Birdfeed 25 Landfill 35 Gift 10 Other 5 a) If a respondent is picked at random, what is the probability that they would use the fruitcake as a doorstop? b) If a respondent is picked at random, what is the probability that they would not use it as birdfeed? 16. a) Explain, clearly and in your own words, the Law of Large Numbers. b) Give an example of an application of the Law of Large Numbers