Question 1: A pizza shop owner wishes to find the 95% confidence interval of the true mean cost of a large pizza. How large a sample is needed is she wants to be accurate to within $0.15 given that a previous study found a standard deviation of $0.26?
Question 2: A recent study showed that 27 residents of Bowie had lived in their homes an average of 11.2 years. The standard deviation was 2. Find the 99% confidence interval of the true mean.