A Machine Cuts Steel to Length for Nails

Short Answer

A machine cuts steel to length for nails. The mean length of a nail is 43 millimeters. There is concern that the settings of the machine producing the nails have changed. To test the claim, twelve nails (n = 12) were sampled. The mean of the sample is 41.5 and the standard deviation 1.784. To decide if the sample data support the claim that mean length is 43 millimeters, state your decision in terms of the null hypothesis. Use a 0.02 level of significance.