3 Questions

This is an exam question of confidence intervals

Questions and Answers

- 1.Achievement Questions 1. A survey is carried out to determine the amount of time children spend watching television each week. A random sample of 200 children gave an average time of 38.6 hours with a standard deviation of 8.4 hours. a) Calculate the standard error of the mean. This is found by theta over root n = 0.544
- A.
True

- B.
False

- 2.1. A survey is carried out to determine the amount of time children spend watching television each week. A random sample of 200 children gave an average time of 38.6 hours with a standard deviation of 8.4 hours.b) Find a 95% confidence interval for the mean number of hours of television watched by all children.
- A.
B) CI = 34.77 < mu < 45.34

- B.
B) CI = 37.44 < mu < 39.76

- C.
B) CI = 37.24 < mu < 39.47

- D.
B) CI = -7.24 < mu < 9.47

- 3.2. The viewing hours of adults are thought to average 21.7 hours with a standard deviation of 7.5 hours. A random survey of 350 adults gives a mean of 23.8 hours. Find a 90% confidence interval for the mean number of viewing hours for all adults.
- A.
A) CI = 23.14 < mu < 29.47

- B.
A) CI = -23.14 < mu < 39.47

- C.
A) CI = 23.14< mu < 29.96

- D.
A) CI = 23.14< mu < 29.96