Question
The quality control manager at a light bulb factory needs to estimate the mean life of a large shipment of light bulbs. The manufacturer's specifications are that the standard deviations is 100 hours. A random sample of 64 light bulbs indicated a sample mean life of 350 hours.
Answers
PsyDAG
With you limited data, the best estimate is 350 hours.
If you want a probability statement,
P = mean ± Z (SEm)
SEm = SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability
(P) and its Z score.
If you want a probability statement,
P = mean ± Z (SEm)
SEm = SD/√n
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability
(P) and its Z score.