- #1

uart

Science Advisor

- 2,776

- 9

Heres the question.

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*The manufacturer’s specifications state that the life of their light globes is normally distributed with a standard deviation of 170 hours.*

What is the mean life, in hours, of these light globes if 97.5% will last up to 5000 hours?

What is the mean life, in hours, of these light globes if 97.5% will last up to 5000 hours?

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The thing that I don't like about this question is that longevity specifications are usually in the form of "9x percent will last

*at least*y hours, whereas here they seem to be saying that they will last

*at most*this many hours.

Does anyone else think that statement "if 97.5% will last up to 5000 hours" could have been better worded. I interpreted it as meaning that 97.5% will last

*at most*5000 hours but I'm wondering if anyone else here might have interpreted it the other way around?