Care was taken to operate a metal casting process so that no assignable causes in variation were introduced, and randomly selected castings were weighed. The target weight of the castings was 28 pounds. The following weights came from 30 random observations. 28.00 27.96 28.01 28.02 28.00 28.01 28.04 28.03 27.94 27.99 27.98 27.99 28.03 27.98 28.01 28.03 28.02 28.02 28.01 28.03 27.98 27.98 28.05 27.96 27.99 28.04 28.00 28.02 28.03 27.96
1. Estimate the standard deviation of the process.
2. What is the Cp if the specifications are 28.0 +/- 0.1 pounds?