A random sample of 11 shearing pins is taken in a study of the Rockwell hardness of the pin head. Measurements on the Rockwell hardness are made for each of the 11​, yielding an average value of 48.50...

A random sample of 11 shearing pins is taken in a study of the Rockwell hardness of the pin head. Measurements on the Rockwell hardness are made for each of the 11​, yielding an average value of 48.50 with a sample standard deviation of 1.6. Assuming the measurements to be normally​ distributed, construct a 95​% confidence interval for the mean Rockwell hardness.