Question

The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The standard deviation is 104 hours. A random sample of 64 light bulbs indicated a sample mean life of 390 hours. Complete parts (a) through (d) below.

Construct a 99 % confidence interval estimate for the population mean life of light bulbs in this shipment.

c. Must you assume that the population light bulb life is normally distributed? Explain.

Answer #1

1. The quality control manager at a light-bulb factory needs to
estimate the mean life of a new type of light-bulb. The population
standard deviation is assumed to be 45 hours. A random sample of 37
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explain a 99% confidence interval estimate of the population mean
life of the new light-bulb.

The quality control manager at a light bulb factory needs to
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standard deviation is 98 hours. A random sample of 49 light bulbs
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population mean life of light bulbs in this shipment.
(Ans.) The 99% confidence interval estimate is from a lower
limit of 263.9 hours to an upper limit of...

The quality control manager at a light-bulb factory needs to
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what size sample would be needed to achieve a margin of error of
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The quality control manager at a light bulb factory needs to
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standard deviation is 91 hours. A random sample of 49 light bulbs
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through (d) below.
A. Construct a 99% confidence interval estimate for the
population mean life of light bulbs in this shipment. The 99%
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The quality control manager at a light bulb factory needs to
estimate the mean life of a large shipment of light bulbs. The
standard deviation is 98 hours. A random sample of 49 light bulbs
indicated a sample mean life of 300 hours.
Suppose the standard deviation changes to 77 hours. What are
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The quality-control manager at a compact fluorescent light
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___ <= MU <= ___ (Round to the nearest whole number as
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standard deviation is
7878
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3636
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280280
hours. Complete parts (a) through (d) below.
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9595%
confidence interval estimate is from a lower limit of
254.5254.5
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The quality-control manager at a compact fluorescent light
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evidence that the mean life is different from 7,463 hours?
b. Compute the p-value and interpret its
meaning.
c. Construct...

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