What proportion of brook trout caught will be between 12 and 18 inches in length?

8. The discrete random variable X is the number of students that show up for Professor Smiths office hours on Monday afternoons. The table below shows the probability distribution for X. What is the expected value E(X) for this distribution?

10. The time required for a citizen to complete the 2000 U.S. Census "long" form is normally distributed with a mean of 40 minutes and a standard deviation of 10 minutes. The slowest 10% of the citizens would need at least how many minutes to complete the form?

11. On average, a major earthquake (Richter scale 6.0 or above) occurs 3 times a decade in a certain California county. What is the probability that less than six months will pass before the next earthquake?

17. On a Sunday in April, dog bite victims arrive at Carver Memorial Hospital at a historical rate of 0.6 victims per day. On a given Sunday in April, what is the probability that exactly two dog bite victims will arrive?

19. If the mean time between unscheduled maintenance of LCD displays in a hospitals CT scan facility is 4,000 operating hours, what is the probability of unscheduled maintenance in the next 5,000 hours?

21. In Melanies Styling Salon, the time to complete a simple haircut is normally distributed with a mean of 25 minutes and a standard deviation of 4 minutes. What percent of customers require less than 32 minutes for a simple haircut?

22. A large number of applicants for admission to graduate study in business are given an aptitude test. Scores are normally distributed with a mean of 460 and standard deviation of 80. What fraction of applicants would you expect to have scores of 600 or above?

23. On average, a major earthquake (Richter scale 6.0 or above) occurs 3 times a decade in a certain California county. Find the probability that at least one major earthquake will occur within
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