Confidence Interval
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The lifetime of a certain brand of battery is known to have a standard deviation of 11.5 hours. Suppose that a random sample of 70 such batteries has a mean lifetime of 43.3 hours. Based on this sample, find a 90% confidence interval for the true mean lifetime of all batteries of this brand. Then complete the table below.
1. What is the lower limit of a 90% confidence interval?
2. What is the upper limit of a 90% confidence interval?
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Solution Summary
The solution contains the determination of the 90% confidence interval for the mean lifetime of a battery.
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(41.039, 45.561) is the 90% confidence interval for the true ...
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