SOLUTION: The lifetime of a certain brand of battery is known to have a standard deviation of 16 hours. Suppose that a random sample of 90 batteries has a mean lifetime of 41.1 hours. Find a
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Question 565140: The lifetime of a certain brand of battery is known to have a standard deviation of 16 hours. Suppose that a random sample of 90 batteries has a mean lifetime of 41.1 hours. Find a 95% confidence interval for the true mean lifetime of all batteries of this brand. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! The lifetime of a certain brand of battery is known to have a standard deviation of 16 hours. Suppose that a random sample of 90 batteries has a mean lifetime of 41.1 hours. Find a 95% confidence interval for the true mean lifetime of all batteries of this brand.
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sample mean: 41.1
margin of error: 1.96*(16/sqrt(90)) = 3.3056
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CI: 41.1 - 3.3056 < u < 41.1 + 3/3056
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Cheers,
Stan H.
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