VARIANCE OF BALL BEARINGS DIAMETER MEASUREMENTS
The random sample of 20 ball bearings diameters X1 , X2 ,... , X20 , pos- tulated in Example 13.4 as being from a Gaussian distribution with μ = 10, resulted in an average measured diameter of x¯ = 9.86 mm, and a standard deviation s = 1.01 mm. Now consider the case in which the design standard deviation for the manufacturing process is speci?ed as σ = 0.9; compute the probability that any sample standard deviation will equal or exceed the observed value of S = 1.01 mm if the manufacturing process is still operating true to the original design speci?cations.