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Test 2
7. According to an almanac, 80% of adult smokers started smoking before turning 18 years old.
(a) Compute the mean and standard deviation of the random variable X, the number of smokers who started before 18 in 100 trials of the probability experiment.
(b) Interpret the mean.
(c) Would it be unusual to observe 85 smokers who started smoking before turning 18 years old in a random sample of 100 adult smokers? Why?
(a)
(b) What is the correct interpretation of the mean?
- It is expected that in 50% of random samples of 100 adult smokers, 80 will have started smoking before turning 18.
- It is expected that in a random sample of 100 adult smokers, 80 will have started smoking before turning 18.
- It is expected that in a random sample of 100 adult smokers, 80 will have started smoking after turning 18.
(c) Would it be unusual to observe 85 smokers who started smoking before turning 18 years old in a random sample of 100 adult smokers?
- Yes, because 85 is between ì−2ó and ì+2ó.
- Yes, because 85 is greater than ì+2ó.
- No, because 85 is less than ì−2ó.
- No, because 85 is between ì−2ó and ì+2ó.
- Yes, because 85 is between ì−2ó and ì+2ó.