Sponsors of a local charity decided to attract wealthy patrons to its $500-a-plate dinner by allowing each patron to buy a set of 20 tickets for the gaming tables. The chance of winning a prize for each of the 20 plays is 50-50. If you bought 20 tickets, what is the chance of winning 15 or more prizes?

Question

Quizplus · Accepted Answer

This problem involves a binomial distribution with n=20 and p=0.5. We want to find the probability of winning 15 or more times, which is the same as finding the probability of winning 14 or fewer times (since these are the only two possibilities). We can calculate this using the binomial cumulative distribution function (CDF) on a calculator, or by using a table. Using the table, we find that the probability of winning 14 or fewer times is 0.979. Therefore, the probability of winning 15 or more times is 1 - 0.979 = 0.021.

Sponsors of a Local Charity Decided to Attract Wealthy Patrons