Questions 15 –17
Personal incomes in a city have an average of $80,000and standard deviation of $20,000.
15. The percent of personal incomes over $100,000 is
(a) 0.05 (b) 0.1 (c) 0.1587 (d) 0.1841 (e) Not enoughinformation to calculate.
16. In a random sample of 100 people, the probability that theaverage income in the sample is over $82,000 is
(a) 0.05 (b) 0.1 (c) 0.1587 (d) 0.1841 (e) Notenough information to calculate.
17. In another random sample of 400 people, the probability thatthe average income in this sample is at least $3,000 more than thesample average income in Question 16 is
(a) 0.03 (b) 0.05 (c) 0.07 (d) 0.09 (e) Not enough informationto calculate.
