Question: A machine produces components whose diameters should be distributed Normally with mean 0.15 cm and Standard Deviation 0.01 cm. It is suspected that the mean may have changed over a long period of use.

To test for this possibility, a sample of 150 components is drawn and the mean is computed at 0.147. Using the assumption that μ is true, determine whether there is any evidence at the 5% level that the mean of the components has changed.