Question:The quality control manager at a light-bulb factory
needs to estimate the mean life of a...
Question
The quality control manager at a light-bulb factory
needs to estimate the mean life of a...
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 50 hours. A random
sample of 35 light-bulbs shows a sample mean life of 490 hours.
Construct and explain a 90% confidence interval estimate of the
population mean life of the new light-bulb. What size sample would
be needed to achieve a margin of error of 15 hours or less? Show
all work.