100 AAA batteries were tested on a particular MP3 player. Suppose the batteries have a mean lifetime of 31.7 hours, with a standard deviation of 2.9 hours. If a battery manufacturer wants all batteries to perform closer to the mean, which of the following should he do?
A. Improve the manufacturing process so the standard deviation is increased.
B. Improve the manufacturing process so the standard deviation is decreased.
C. Improve the manufacturing process so the mean lifetime is decreased.
D. Improve the manufacturing process so the mean lifetime is increased.

Question

100 AAA batteries were tested on a particular MP3 player. Suppose the batteries have a mean lifetime of 31.7 hours, with a standard deviation of 2.9 hours. If a battery manufacturer wants all batteries to perform closer to the mean, which of the following should he do?
	A.	Improve the manufacturing process so the standard deviation is increased.
	B.	Improve the manufacturing process so the standard deviation is decreased.
	C.	Improve the manufacturing process so the mean lifetime is decreased.
	D.	Improve the manufacturing process so the mean lifetime is increased.

kropot72 · Answer

The variability of the process must be reduced. The standard deviation must be decreased.