A film alliance used a random sample of 35 U.S. citizens to estimate that the typical American spent 78 hours watching videos and DVDs last year. The standard deviation of this sample was 9 hour.
Develop a 95% confidence interval for the population mean number of hours spent watching videos and DVDs last year.
Suppose the film redoes the study on 3,500 randomly selected U.S. citizens and find the sample mean and standard deviation are same as before. Please reconstruct the 95% confidence interval based on the sample of size 3,500.
Compare the two confidence intervals constructed in part a and part b. How are they different from each other? What may you conclude based on the difference between the two confidence intervals.