Answers

  • Brainly User
2014-03-25T14:31:06+05:30
By seeing the data  we can see this is normal distribution
Z= \frac{X-U}{S.D}= \frac{2000-3000}{400}=-2.5
P(X<2000)=P(Z<-2.5)=0.5-P(2.5 >Z>0)
Due to symmetry
P(X<2000)=0.5-0.0062=0.4938
probability it willhave a mean life less than 2000 hours is 0.4938
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