The diameter of a metal shaft used in a disk-drive unit is normally distributed with mean XXXXXXXXXXin. and std. dev XXXXXXXXXXin. The specification on the shaft have been established as XXXXXXXXXXin,...

The diameter of a metal shaft used in a disk-drive unit is normally distributed with mean 0.2508 in. and std. dev. 0.0005 in. The specification on the shaft have been established as (0.25-0.0015 in, 0.25+0.0015in) What fraction of the shafts produced conform to specifications?

a). 0 b). 0.08 c). 0.16 d). 0.92