Question-) 100 specimens are tested in determining the life cycle of a certain type of crank shaft which is used in a particular brand of car engine. The tests have shown an average life cycle of μ=44...

Question-)

100 specimens are tested in determining the life cycle of a certain type of crank shaft which is used in a particular brand of car engine. The tests have shown an average life cycle of μ=44 Gc (1 Gc = 1 gigacycles = 109 cycles) and a standard deviation of σ=33x10-1 Gc. 200 hundred thousand cars using that engine have been sold and are on the traffic. After what number of Gigacycles would you expect 7 % of the shafts broken down?