Stats Final Quiz

1) A study of 180 randomly selected American Airlines flights showed that 68 arrived late. What is the estimated probability of an American Airlines flight arriving on time?

2) If you make random guesses for four multiple choice test questions (each with 4 possible answer), what is the probability of getting at least one correct?

3) If you know the names of the starting batters for a baseball team, what is the probability of randomly selecting a batting order and getting the order that it is used in the beginning of the game? Remember that there are nine players in a batting order.

4) In a certain experiment M & M candies are randomly grouped in bags of 30 pieces each. If 14% of all such candies are red, what will be the mean and standard deviation of the number of red pieces per bag? Would it be unusual for 9 out of 30 of these M & M's to be red?

5) The Flamerock Tire Company manufactures a particular tire model that has a mean lifetime of 65,000 miles with a standard deviation of 4,500 miles. The lifetimes are normally distributed. What is the probability that one of these tires selected at random will last 70,000 miles or more?