SOLUTION: The life of electronic bulb follows a normal distribution with mean life of 3000 hours and standard deviation of 200 hours. what is the probability that a tube lights has more life

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Question 1191990: The life of electronic bulb follows a normal distribution with mean life of 3000 hours and standard deviation of 200 hours. what is the probability that a tube lights has more life than 3400 hours??
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(x-mean)/sd
=400/200
=2
The probability z is > 2 is 0.0228.