In: Statistics and Probability
(1) Many people consider their smart phone to be essential! Communication, news, Internet, entertainment, photos, and just keeping current are all conveniently possible with a smart phone. However, the battery better be charged or the phone is useless. Battery life of course depends on the frequency, duration, and type of use. One study involving heavy use of the phones showed the mean of the battery life to be 11.75 hours with a standard deviation of 3.4 hours. Then the battery needs to be recharged. Assume the battery life between charges is normally distributed. (a) Find the probability that with heavy use, the battery life exceeds 12 hours. (Round your answer to four decimal places.) (b) You are planning your recharging schedule so that the probability your phone will die is no more than 5%. After how many hours should you plan to recharge your phone? (Round your answer to the nearest tenth of an hour.) -------hours (2) The University of Montana ski team has six entrants in a men's downhill ski event. The coach would like the first, second, and third places to go to the team members. In how many ways can the six team entrants achieve first, second, and third places? (3) Find z such that 15% of the area under the standard normal curve lies to the right of z. (Round your answer to two decimal places.) Incorrect: Your answer is incorrect.