A quality analyst desires to develop the sample mean chart for controlling the packaging process. He knows from past experience which the procedure standard deviation is two ounces. Each day last week, he randomly chosen four packages and weighed each. The data from that activity appears below.
|
Weight
|
|
Day
|
Package 1
|
Package 2
|
Package 3
|
Package 4
|
|
Monday
|
23
|
22
|
23
|
24
|
|
Tuesday
|
23
|
21
|
19
|
21
|
|
Wednesday
|
20
|
19
|
20
|
21
|
|
Thursday
|
18
|
19
|
20
|
19
|
|
Friday
|
18
|
20
|
22
|
20
|
a) Evaluate the upper and lower control limits for the both sample means and ranges.
b) Is this process in control? Explain simple Yes or No is insufficient.
c) What additional steps must the quality assurance team capture?