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The life of a battery is normally distributed with an avergae life of 50 hours and a standard deviation of 7 hours. What is the probablity that a randomly chosen battery will have a life between 57 and 64 hours?
a) 34%
b)68%
c)13.5%
d)47%
e)27%
I thought the answer was b because 57- 64 is 2 standard deviations above the mean which is 68%, but I guess I'm wrong.
The answer is c
Any suggestion to how its c?
a) 34%
b)68%
c)13.5%
d)47%
e)27%
I thought the answer was b because 57- 64 is 2 standard deviations above the mean which is 68%, but I guess I'm wrong.
The answer is c
Any suggestion to how its c?