試題詳解

複選題
10. Suppose that the mean daily TV viewing time per household follows a normal distribution with a mean of 5 hours and a standard deviation of 2 hours. Which of the following is/are correct?
(A) The probability that a household views TV more than 3 hours a day is 0.1587；
(B) The probability that a household views TV between 4-7 hours a day is 0.5328；
(C) In order to be in the bottom 10% of all TV viewing households, a household has to view TV for less than 2.44 hours a day；
(D) Among a group of households that all members are obese (BMI>=35), we randomly selected a sample of 16 households to investigate whether the mean of their TV viewing time is longer than that of the population mean. We found that the sample mean was 6.5 hours. To conduct a one-tailed z-test with a-0.05, the z-score=3.
(E) From ( D ), we can conclude that households with all obese members have longer TV viewing time than the population with the p-value=0.0013, based on the one-tailed z-test.