Assume the mean useful life of a particular light bulb is 2,000 hours and is normally distributed with a standard deviation of 300 hours. Calculate the useful life of light bulbs within two standard deviations of the mean.

Question

anonymous · Answer

well its between 2000 and 2600 hours. tbh i dont really understand your question

anonymous · Answer

Assume the mean useful life of a particular light bulb is 2,000 hours and is normally distributed with a standard deviation of 300 hours. Calculate the useful life of light bulbs within two standard deviations of the mean. 





Between 1,400 and 2,600 hours 





Between 1,700 and 2,300 hours 





Longer than 1,700 hours 





Longer than 2,300 hours

anonymous · Answer

The above post is exactly how the question reads, I just copied and pasted it.

anonymous · Answer

Dose this help??

anonymous · Answer

oh right, well 2000-300-300=1400 and 2000+300+300=2600, hence between 1400 and 2600.

anonymous · Answer

Ok now I see!!! Thank You!!!!!!!!!!!

anonymous · Answer

I was only going plus and minus 300, and not doubling it!