A random sample of 19 shearing pins is taken In a study 01 the Rockwell hardness of the pin head, Measurements on the Rockwell hardness are made for each of the 19' yielding an average value M45 50 With a sample standard deviation M13 Assuming the measurements to be normally distributed, construct a 90% condence interval for the mean Rockwell hardness Click here to View {gs 1 of the standard normal distribulion table, Cl k here to w {gs 2 of the standard rrnal distribulion ta w {gs 1 of the table of critical values Hi the Cl k here to view {age 2 of the table of critical values olthe tidis bu on. The condence interval is