SOLUTION: The average lifespan for batteries is 90 hours with a standard deviation of 12 hours. Construct a confidence interval at the 95% confidence level.

Question 233879: The average lifespan for batteries is 90 hours with a standard deviation of 12 hours. Construct a confidence interval at the 95% confidence level.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The average lifespan for batteries is 90 hours with a standard deviation of 12 hours. Construct a confidence interval at the 95% confidence level.
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sample mean: 90
standard error: 1.96*12 = 23.52
95% CI: 90-23.52 < u < 90+23.52
95% CI: 66.48 < u < 113.52
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Cheers,
Stan H.
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