Pleasantville Steel Works stamps/produces O-rings for various metal-workcompanies. The metal-work companies expect the O-rings to have a diameter of30 cm. The machine that makes these O-rings does not always produce each Oring with a diameter of exactly 30 cm (sometimes, metal shards are left behindafter pressing and affect the next O-ring) and consequently, the O-rings can varyslightly.When the machine is working properly, the O-rings made on this machine have amean diameter of exactly 30 cm. The standard deviation of the diameters of allO-rings produced on this machine is always equal to 0.5 mm. The quality controldepartment takes a random sample of 35 such O-rings every week, calculates themean of those diameters for these O-rings, and makes a 99% confidence intervalfor the population mean. If either the lower limit of this confidence interval isless than 29.9500 cm or the upper limit of this confidence interval is greater than30.04 cm, the machine must be stopped and re-calibrated/adjusted. During the1st week of March 2021, a sample of 35 rings produced a mean diameter of30.0250 cm.Based on this sample, can you conclude that the machine needs (or doesn’t need)to be re-calibrated/adjusted? Explain/justify your conclusion.
Already registered? Login
Not Account? Sign up
Enter your email address to reset your password
Back to Login? Click here