Exercise 4: The soft-drink cups at a certain fast-food restaurant have tickets attached to them. Customers peel off the tickets to see if they win a prize. The proportion of winning tickets is 25%. A total of 70 people purchased soft-drinks between noon and 1:00 pm on a certain day. a) What is the probability that at least a third of the people playing win a prize? b) Using the 2-SD rule, what is the \"usual range\" of winning percentages we can expect? c) If our local store in this chain reported having a sample proportion of winners that was representative of the 85th percentile of all stores carrying these tickets, what percentage of winners did they observe in their store