7.105 Average hours per week listening to the radio. Refer to the previous exercise. The Student Monitor also reported that the average amount of time listening to the radio was 11.5 hours.
(a) Given an estimated standard deviation of 5.2 hours, what sample size is needed so that the expected margin of error of your estimate is not larger than one hour for 95% confidence?
(b) If your survey is going to ask about Internet use and radio use, which of the two calculated sample sizes should you use? Explain your answer.