The quality control manager of Ridell needs to estimate the meanbreaking point of a large shipment of helmets sent to thePhiladelphia Eagles. Given the production process, the knownstandard deviation of the population of breaking points is 15.5lbs. A random sample of 49 helmets were selected and subjected toincreasing pressure until every one of them broke. The breakingpoint of each helmet was recorded, and average breaking point ofthe sample was 150 lbs.
What are the critical values from the z distribution associatedwith a 95% confidence interval?
