According to an almanac, 70% of adult smokers started smoking before turning 18 years old. (a) if 200 adult smokers are rando
mly selected, how many would we expect to have started smoking before turning 18 years old? (b) would it be unusual to observe 160 smokers who started smoking before turning 18 years old in a random sample of 200 adult smokers? why?
Solution: (a) if 200 adult smokers are randomly selected, how many would we expect to have started smoking before turning 18 years old?
Answer: It is expected that in a random sample of 200 adult smokers, will have started smoking before turning 18.
(b) would it be unusual to observe 160 smokers who started smoking before turning 18 years old in a random sample of 200 adult smokers? why?
Answer: Yes, it would be unusual to observe 160 smokers who started smoking before turning 18 years old in a random sample of 200 adult smokers, because 160 is greater than μ + 2σ
