a metal washer fabrication machine makes metal washes with a Target diameter of u=10.5 millimeters. the machine has some variability Southeast standard deviation of the diameter is o= 0.003 millimeters. same machine operator inspects a random sample of 9 washers each hour quality control purposes and record the sample mean diameter, x. assuming the process is working properly what are the mean and standard deviation of the sampling distribution of x?​