A corporation that manufactures field rifles for the Department of Defense operates a production line that turns

Question:

A corporation that manufactures field rifles for the Department of Defense operates a production line that turns out finished firing pins. To monitor the process, an inspector randomly selects five firing pins from the production line, measures their lengths (in inches), and repeats this process at 30-minute intervals over a 5-hour period.

a. Use the data for the 10 time periods listed in the table below to calculate the center line for x̅-chart.

b. Compute upper and lower control limits.

c. Calculate and plot the 10 sample means to form an x̅-chart for the firing pin lengths.

d. Suppose the Defense Department’s specification for the firing pins is that they be 1.00 inch plus or minus .08 inch in length. Does the manufacturing process appear to be in control?