The tensile strength of sheet metal screws is monitored by selecting a sample of 4 screws at 30-minute intervals, then seeing how many pounds of force are required to break each screw. Given the following data, also listed in file XR20043, construct 3-sigma mean and range control charts and evaluate whether the process is in control.

Transcribed Image Text:

Pounds, Screw Number Sample Number 4 760 843 800 809 875 770 927 739 810 747 876 873 728 706 742 754 763 939 956 787 710 4 5 718 988 843 792