The quality control manager of a major cell phone provider is concerned about the life of the cell phone batteries they use. He took a sample of 13 batteries from a recent shipment and used them continuously until they failed to work. The manager measured the number of hours the batteries lasted and found the mean to be 550.4 with a standard deviation of 315.3.
-How much evidence do we have that the mean life is more than 400 hours?
A)No evidence
B)Some evidence
C)Strong evidence
D)Very strong evidence
E)Extremely strong evidence

Question

Quizplus · Accepted Answer

The sample mean is significantly higher than 400 hours, but the large standard deviation and small sample size mean the evidence is not very strong.

The Quality Control Manager of a Major Cell Phone Provider