The jig in Exercise 25 is now OK, except we are getting too many undersized rods passing specifications. The manufacturing section of your company wants to eliminate all rods 0.2 mm or more that are undersized so that L = 21.0 mm is the lower cutoff. What fraction will now pass specifications?

Exercise 25.

We wish to fit steel rods (µ = 21.2 mm, σ = 0.20 mm) into the following jig in order to make sure we can meet specifications. The process requires that 97.5% of all rods are to be within specifications. (Presume that no rod is so short that it cannot pass specifications.) What is the appropriate size L mm of the jaws of the jig? 95% of (two-sided) normally distributed data are found within ± 2σ from the mean and therefore 2.5% of the rods are too large.

FAILED TOO SHORT % = ? FAILED 2.5% 21.0 mm 21.2 mm Lmm (from Exercise 25)