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

Question

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

Quizplus · Accepted Answer

X-bar (sample mean) is the sum of all the observations divided by the total number of observations. The given sample of six tubes has the following weights: 6.67, 6.80, 6.73, 6.75, 6.74, and 6.73 ounces. To find X-bar for 7 am, we need to take the mean of these six observations, which is (6.67+6.80+6.73+6.75+6.74+6.73)/6 = 6.74 ounces. Therefore, the answer is B) 6.74.

A New Machine Is Set or Calibrated to Fill Tubes