Question 78748
A random sample of 56 fluorescent light bulbs has a mean life of 645 hours with a standard deviation of 31 hours. Construct a 95% confidence interval for the population mean.
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x-bar = 645
E=1.96[31/sqrt(56)]=8.1194
The 95% confidence interval is 645-8.1194<=mu<=645+8.1194
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Cheers,
Stan H.