Question 386068: The lifetime of a Duracell AAA battery is normally distributed with a mean M=28.5 hours and standard deviation baby sigma= 5.3 hours. Compute z scores to determine for a battery selected at random, what is the probability is that the lifetime will be
a.) 25 hours or less
b.) 34 hours or more
c.) between 25 hours and 34 hours.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The lifetime of a Duracell AAA battery is normally distributed with a mean M=28.5 hours and standard deviation baby sigma= 5.3 hours. Compute z scores to determine for a battery selected at random, what is the probability is that the lifetime will be
a.) 25 hours or less
z(25) = (25-28.5)/5.3 = -0.6604
P(x <= 25) = P(z <= -0.6604) = 0.2545
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Cheers,
Stan H.
b.) 34 hours or more
Prob = 0.1497
c.) between 25 hours and 34 hours.
Prob = 0.5960
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Cheers,
Stan H.
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