Question: A sample survey of 54 discount brokers showed that the mean price chard for a trade of 100 shares at $50 per share was 533.77 (AM' Journal. February 2006). The survey is con-ducted annually. With the historical data available, assume a known population standard deviation of S15.
a. Using the sample data. what is the margin of error associated with a 95th confidence intenal?
b. Develop a 95% confidence interval for the mean price charged by discount brokers for a trade of 100 shares at $50 per share.