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File Edit View History Bookmarks Profiles Tab Window Help iz: Final Exam 100% Thu 8:41:17 PM tulane.instructure.com/courses/2232989/quizzes/4104127/take chance that a motor's lifespan exceeds c. The lifespan of a certain brand of an electric motor is normally distributed with a mean value of 10 with a standard deviation of 3 years. Find the 80% percentile of the motor lifespans, i.e., find a value c so that there is an 80% chance that a randomly selected motor's lifespan is less than c, and there is a 20% 12.68 12.52 12.84 11.68 0 252 D Question 18 3 pts An um contains 6 red balls and 4 yellow balls. If we randomly select 3 balls from the urn without replacement, what is the probability that we obtain 1 red ball and 2 yellow balls? 47/120 0 7/40 3/10 O 1/2 5 4/10 D Question 19 3 pts function for Y, find f(7). Suppose that 40% of fruit flies possess a certain gene. We will randomly select fruit flies until we have found 3 flies with the gene. Let Y = 0, 1, 2, 3, 4, 5, . . . be the random variable defined as the number of flies we must be select so that we obtain three flies with the gene. If f(y) denotes the probability 0.1045 6 0.0838 0.1244 0.1382 0.1529 D Question 20 3 pts If we have a population of 9 objects, in how many ways may we select a sample of 5 objects from the population. Assume we use sampling without replacement and the order of the elements in the sample does not matter. 126 21 6720 15120 10 56 4 MAY ... 6