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ved A Quality Analyst wants to construct a sample mean chart for controlling a p

ID: 325397 • Letter: V

Question

ved A Quality Analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is under control, package weight is normally 5 distributed with a mean of twenty ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each: Day Monday Tuesday Wednesday Thursday Friday 23 22 23 24 23 21 19 21 20 19 20 21 18 19 20 19 18 20 22 20 10 14 What is the sample mean package weight for Thursday?

Explanation / Answer

Weights of the four samples for thursday

Sample 1 = 18 ounces

Sample 2 = 19 ounces

Sample 3 = 20 ounces

Sample 4 = 19 ounces

The mean of the package weights for Thursday, is the average of the package weights i.e.

Mean = (Sum of the Package weights) / Number of packages

= (18 + 19 + 20 + 19) / 4

= 76 / 4

= 19 ounces

Hence sample mean package weights for Thursday = 19 ounces