Use the following table to answer the question(s) below.

-A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the center line be for a chart that monitors process average?
A) 4.58
B) 4.66
C) 4.73
D) 4.78
E) 4.82

Question

Use the following table to answer the question(s) below.
 
-A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the center line be for a chart that monitors process average?
A) 4.58 
B) 4.66 
C) 4.73 
D) 4.78 
E) 4.82

Quizplus · Accepted Answer

The center line for a chart that monitors process average is the average of the sample means. The sample means are already calculated in the table, so we just need to find their average. Adding up the sample means and dividing by the number of samples gives us:

(4.68 + 4.72 + 4.78 + 4.70 + 4.75 + 4.71 + 4.67 + 4.73) / 8
= 37.74 / 8
= 4.71875

Rounding to two decimal places gives a center line of 4.73, which is answer choice C.

Use the Following Table to Answer the Question(s) Below