10. If x, the time (in minutes) to complete an change job at certain auto service station, is uniformly distributed over the interval 20 to 30, inclusively (20 x 30), then the probability that an oil change job will be completed in exactly 25 minutes, i.e., P(x = 25) is __________________. a) 0.750 b) 0.333 c) 0.000 d) 0.500 e) 0.900 20. Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > 2.4)? a) 0.0082 b) 0.4918 c) 0.9918 d) 0.4793 e) 0.0820 22. Let z be a normal random variable with mean 0 and standard deviation 1. What is P(z > -1.1)? a) 0.8643 b) 0.36432 c) 0.1357 d) -0.1357 e) -0.8643 23. Let z be a normal random variable with mean 0 and standard deviation 1. What is P(-2.25 < z < -1.1)? a) 0.3643 b) 0.8643 c) 0.4878 d) 0.1235 e) 0.5000 According to a report by Scarborough Research, the average monthly household cellular phone bill is $60. Suppose local monthly household cell phone bills are normally distributed with a standard deviation of $11.35. Answer questions 28-31 based on the above information. 28. What is the probability that a randomly selected monthly cell phone bill is more than $85? e) 0.0139 b) 0.4861 c) 0.9861 d) 0.6139 e) 0.5000 29. What is the probability that a randomly selected monthly cell phone bill is between $45 and $70? a) 0.8106 b) 0.9066 c) 0.4066 d) 0.7172 e) 0.3106 30. What is the probability that a randomly selected monthly cell phone bill is between $65 and $75? a) 0.6700 b) 0.1700 c) 0.4066 d) 0.0934 e) 0.2366 31. What is the probability that a randomly selected monthly cell phone bill is no more than $40? a) 0.4987 b) 0.0392 c) 0.5000 d) 0.9608 e) 0.4608 A study about strategies for competing in the global marketplace states that 52% of the respondents agreed that companies need to make direct investments in foreign countries. It also states that about 70% of those responding agree that it is attractive to have a joint venture to increase global competitiveness. Suppose CEOs of 95 manufacturing companies are randomly contacted about global strategies. Using Normal Approximation of Binomial Distribution with correction for continuity, answer questions 35-38 based on above information. 35. What is the probability that between 44 and 52 (inclusive) CEOs agree that companies should make direct investments in foreign countries? a) 0.3869 b) 0.2389 c) 0.5013 d) 0.6258 e) 0.7389 36. What is the probability that more than 56 CEOs agree with that assertion? a) 0.0721 b) 0.4279 c) 0.8279 d) 0.5000 e) 0.5721 37. What is the probability that fewer than 60 CEOs agree that it is attractive to have a joint venture to increase global competitiveness? a) 0.5000 b) 0.4418 c) 0.9418 d) 0.0582 e) 0.5582 38. What is the probability that between 55 and 62 (inclusive) CEOs agree with that assertion? a) 0.1830 b) 0.9963 c) 0.3133 d) 0.8099 e) 0.4963 39. The average length of time between arrivals at a turnpike tollbooth is 23 seconds. Assume that the time between arrivals at the tollbooth is exponentially distributed. What is the probability that a minute or more will elapse between arrivals? a) 0.9265 b) 0.0435 c) 0.0735 d) 0.4365 e) 0.5000 40. The average length of time between arrivals at a turnpike tollbooth is 23 seconds. Assume that the time between arrivals at the tollbooth is exponentially distributed. If a car has just passed through the tollbooth, what is the probability that no car will show up for at least 3 minutes? a) 0.9996 b) 0.4996 c) 0.0004 d) 0.0435 e) 0.9265