Multiple Choice
A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results:
What is the standard deviation of the sampling distribution of sample means for whenever service life is in control?
A) 5 hours
B) 6.67 hours
C) 10 hours
D) 11.55 hours
E) 20 hours
Correct Answer:
Verified
Correct Answer:
Verified
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