The bending strength of the poles is a consideration to a manufacturer of fiberglass fishing rods. Samples are chosen from the process, and the average bending strength of four samples is found. The target mean bending strength is 30 kg, with a process standard deviation of 0.8 kg. Suppose that it is desired to detect a shift of 0:75 from the target value.
If the process mean is not significantly different from the target value, it is also desirable for the average run length to be 300. Find the parameters of an appropriate V-mask.
If the manufacturer desires that the average run length not exceed 13 so as to detect shifts of the magnitude indicated, what will be the parameters of a V-mask if there is some flexibility in the allowable ARL when the process is in control?