The life span of a battrery is normally distributed with a mean of 2100 hours and a standard deviation of 20 hours. What percent of batteries have a life span more than 2125 hours? would it be unusual for a battery to have a life span that is more than 2125 hours?

Question

anonymous · Answer

Use the chart to find how much of the normal distribution is above z = 1.25.  I think it happens often enough that you wouldn't think it to be too unusual.

anonymous · Answer

By my reckoning, it happens a little more than 10% of the time.

anonymous · Answer

I'm a little older, so I use the chart from a book; you may have a way to do it on a calculator or computer.

anonymous · Answer

LOL so am I. I used a chart.

anonymous · Answer

Do math every day.