A control chart with 3-sigma limits is to be established for the fraction nonconforming

using a centre line of ?? = 0.1.

a) If the process mean shifts to ??1= 0.2, what sample size is required if we wish to detect

this shift on the next sample following the shift with probability at least 0.5, and

have the lower control limit positive? Use Poisson tables if normal approximation is

not good.

b) For the shift to ??1, determine the minimum sample size for the control chart with

3-sigma limits for which the average run length is less than or equal to 5.