Question

The diameters of ball bearings are distributed normally. The mean diameter is 120 millimeters and the standard deviation is 4 millimeters. Find the probability that the diameter of a selected bearing is greater than 125 millimeters. Round your answer to four decimal places.

Answer 1

µ =    120                  
σ =    4                  
                      
P ( X > 125   ) = P( (X-µ)/σ ≥ (125-120) / 4)              
= P(Z > 1.25   ) = P( Z <   -1.250   ) =    0.1056   (answer)