An insurance company auditor takes eight samples of 250 completed forms to establish control limits for the fraction of insurance policy forms that are filled out incorrectly.The data appear in this table:

-What is the center line for the appropriate chart?

Question

An insurance company auditor takes eight samples of 250 completed forms to establish control limits for the fraction of insurance policy forms that are filled out incorrectly.The data appear in this table:
 
-What is the center line for the appropriate chart?

Quizplus · Accepted Answer

The center line for the chart is the mean of the sample proportions, which is calculated by adding up all of the proportions and dividing by the number of samples: (1/250 + 7/250 + 3/250 + 5/250 + 12/250 + 5/250 + 2/250 + 6/250) / 8 = 41/1000 = 0.041. Rounded to four decimal places, the center line is 0.0435, which corresponds to choice C.

An Insurance Company Auditor Takes Eight Samples of 250 Completed