A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that the process standard deviation is two kilograms (2 kg). On each of the 5 working days, last week, he randomly selected four packages and weighed each. The data from that activity appears below.

Question: Calculate the UCL and the LCL for the X-bar chart, using for natural variations.

	Package Weights
Day	Package 1	Package 2	Package 3	Package 4
Monday	20	22	24	22
Tuesday	23	21	19	21
Wednesday	20	19	20	21
Thursday	18	19	20	19
Friday	19	21	23	21

1. UCL = 41.5; LCL = 39.7
2. UCL = 22.6; LCL = 18.6
3. UCL = 11.6; LCL = 19.1
4. UCL = 31.2; LCL = 29.4
5. UCL = 23.6; LCL = 17.6

Based on the information in the previous SPC question (# 5), is this process in control or out of control?

1. Process is in control
2. Process is out of control
3. This analysis should have used a p-chart
4. Not enough information given to answer this question
5. All of the above