To find the probability that the average length of a sheet is between 30.205 and 30.305 inches long.
The population of lengths of aluminium coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.20 inches. A sample of four metal sheets is randomly selected from a batch. What is the possibility that the average length of a sheet is between 30.205 and 30.305 inches long?