Question

C&A is making steel rods with an average diameter of 1 mm. The process has a standard deviation of 0.2 mm. The upper and lower specification limits are 1.2 mm and 0.8 mm respectively. What is the probability that the rod’s diameter will either be too wide or too narrow?

Answer 1

The standard deviation is given as 0.2 mm.

The upper and lower limits are given as 1.2 and 0.8, which is 1 standard deviation.

Using the 68-95-99.7 rule, 68% of the rod's would be within the 1 standard deviation.

This means 32% ( 100 - 68 = 32) would either be too wide or too narrow.