1.) Salespeople for a business machine company have average annual sales of $200,000, with a standard deviation of $20,000. What percentage of the salespeople would be expected to make annual sales of $240,000 or more? Assume a normal distribution.
2.) The average lifetime for a car battery of a certain brand is 170 weeks, with a standard deviation of 10 weeks. If the company guarantees the battery for 3 years, what percentage of the batteries sold would be expected to be returned before the end of the warranty period? Assume a normal distribution.
3.) Three coins are tossed. What is the conditional probability that the outcome is HHH, given that at least two heads occur?