In previous problem 20.4, the design specification on the part is that the critical cross-sectional dimension = 28.0 ( 2.0 mm.
(a) What proportion of parts fall outside the tolerance limits?
(b) If the process were adjusted so that its mean diameter = 28.0 mm and the standard deviation remained the same, what proportion of parts would fall outside the tolerance limits?
(c) With the adjusted mean at 28.0 mm, determine the value of the process capability index.
Problem 20.4
A plastic extrusion process is in statistical control and the output is normally distributed. Extrudate is produced with a critical cross-sectional dimension = 28.6 mm and standard deviation = 0.53 mm.