1. A company wants to monitor its bottle filling process. Random samples of four bottles were taken from the production line every 20 minutes to measure the volume of liquid in each bottle. Results are included in the following table:
Sample Millimeters in each bottle
1 351.2 350.9 350.6 350.7
2 350.3 351.0 351.1 350.8
3 351.4 350.9 351.3 351.2
4 350.8 350.5 351.1 350.1
5 350.6 350.9 351.4 351.1
a. Is the volume of liquid in a bottle a variable or an attribute?
b. What kind of control chart should be used to monitor the average volume of liquid in each bottle? Determine the three-sigma control limits for this chart.
c. Plot the average bottle volume for each sample on the appropriate chart. Is the process in-control with respect to the average volume? What action should be taken?
d. What kind of control chart should be used to monitor the spread or dispersion of values? Determine the three-sigma control limits for this chart.
e. Plot the volume range for each sample on the appropriate chart. Is the process in-control with respect to the volume range? What action should be taken?