Question: A quality analyst wants to construct a sample mean chart for controlling a packaging process. Each day last week, he randomly selected six packages and

A quality analyst wants to construct a sample mean chart for controlling a packaging process. Each day last week, he randomly selected six packages and weighed each. The data from that activity appears below.

Weight (in grams)

Day

Package 1

Package 2

Package 3

Package 4

Package 5

Package 6

Monday

23

22

23

24

23

21

Tuesday

23

21

19

21

24

20

Wednesday

20

19

20

21

19

20

Thursday

18

19

20

19

21

22

Friday

18

20

22

20

19

21

To assist students, I am attaching the Factors for Determining Control Limits from your text

Sample size A2 D3 D4

2 1.880 0 3.268

3 1.023 0 2.574

4 0.729 0 2.282

5 0.577 0 2.115

6 0.483 0 2.004

7 0.419 0.076 1.924

8 0.373 0.136 1.864

9 0.337 0.184 1.816

10 0.308 0.223 1.777

12 0.266 0.284 1.716

Assuming three (3) sigma limits (corresponding to 99.73 percent), construct:

  1. the upper and lower control limits for a Mean chart; (3 marks)

  1. the upper and lower control limits for a Range chart; (3 marks)

Examining the data and your constructed charts from above, is the process in control, heading out of control or already out of control? Briefly justify your answer in no more than 1-2 sentences (60 words maximum).

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