A New Machine Is Set or Calibrated to Fill Tubes

Multiple Choice

A new machine is set or calibrated to fill tubes of toothpaste at precisely 6.75 ounces. Then, once the machine is running, a sample of six tubes is taken every three hours and weighed with the following results: What is X-bar for 7 am?

A) 6.72
B) 6.74
C) 6.78
D) 6.80