Question

8. A machine is producing metal parts that are cylindrical in shape. A sample of 36 parts are taken and the average diameter was found to be 3.2 mm. Find a 95 percent confidence interval for the mean diameter of pieces for this machine. Assume a normal distribution. a) Find the 95 % Confidence intervals for the mean diameter. Assume that the population standard deviation is 0.25 b) How large a sample is required if we want to be 95% confident that your estimate of the mean is off by less than 0.05?

Answer 1