ECON 302-The population of lengths of aluminum-coated steel sheets

Subject: Mathematics    / Statistics
Question
8. The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.0 inches and a standard deviation of 0.70 inches. A sample of 25 metal sheets is randomly selected from a batch. What is the probability that the average length of a sheet is between 30.08 and 30.32 inches long?