Question: Let μ be the hourly wage (excluding tips) for workers who provide hotel room service in a large city. A random sample of a number (more than 30) of such workers yielded a 95% confidence interval for of $8.46 to $9.86 using the normal distribution with a known population standard deviation.
a. Find the value of for this sample.
b. Find a 99% confidence interval for μ based on this sample.