Question 650680: A random sample of 1000 light bulbs shows that the mean life is 600 hours with a standard deviation of 50 hrs. If we know that the distribution is not normal, at least 89% of light bulbs will between which two amounts of ours.
They didn't gave me the k, and I don't know how to find it. Can you please help.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A random sample of 1000 light bulbs shows that the mean life is 600 hours with a standard deviation of 50 hrs. If we know that the distribution is not normal, at least 89% of light bulbs will between which two amounts of ours.
They didn't gave me the k, and I don't know how to find it. Can you please help.
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Chebychev says at least 1-(1/k)^2 of the population is within k
standard deviations of the mean.
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Solve 1- (1/k)^2 = 0.89
k = 3
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Lower limit of light life: 600-3*50 = 450
Upper limit of light life: 600+3*50 = 750
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Cheers,
Stan H.
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