1.X-barand R charts are to be set up samples of size is n = 4, andand r are computed for each of30 preliminary samples as follows:

,

a)Calculate trial control limits for X-bar and R charts. (20 points)

b)Estimate the process mean and standard deviation. (20 points)

c)Suppose that the quality characteristic is normally distributed with specification at 220+40. What is the fallout level? Estimate the process capability ratio (Cp). (20 points)

2.Discuss type I and type II errors relative to the control chart. What practical implication in terms of process operation do these two types of errors have? (30 pts)