Hello I need help answering question 9 with work shown so I

9. According to flightstats com, American Airlines flights rom Da asto Chicago are on time 80% of the e time Suppose that 15 lights are randomly selected, and the number of on time flights is recorded. Lo. a) Explain why this is a binomial random variable. (b) Find the pobability that exactly 4 fights are on time. (c) Find the probability that less than 6 flights are on time. (d) Find the probability that at least 10 flights are on time. 10. According to the American Lung Association, 90% of adult smokers started smoking before 21 years old Ten smokers 21 years old or older are randomly selected, and the number of smokers who started smoking before 21 is recorded. n D (a) What is the expected number of smokers who started smoking before the age of 21? (b) What is the standard deviation 11. Ball bearings are manufactured with a mean diameter of 5 mm and standard deviation of 0.02 mm. num rofa okrs . ID=9 dard What proportion of ball bearings has a diameter greater than 5.057 12. The mean annual income for people in a certain city (in thousands of dollars) is 42, with a standard deviation of 30. A pollster draws a sample of 90 people to interview. bo emple mean income is less than 35?

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