1) C-Spec, Inc., is attempting to determine whether an existing machine is capable of milling an engine part that has a key specification of 4+6 .003 inches.
After a trial run on this machine, C-Spec has determined that the machine has a sample mean of 4.001 inches with a standard deviation of .002 inch.
a. Calculate the Cpk for this machine.
b. Should C-Spec use this machine to produce this part? Why?
2) Ten samples of 15 parts each were taken from an ongoing process to establish a p-chart for control. The samples and the number of defectives in each are shown in the following table:
Number of Number of Defective Items Defective Items Sample n in the Sample Sample n in the Sample
1 15 3 6 15 2
2 15 1 7 15 0
3 15 0 8 15 3
4 15 0 9 15 1
5 15 0 10 15 0
a. Develop a p-chart for 95 percent confi dence (1.96 standard deviation).
b. Based on the plotted data points, what comments can you make?