Posted by **sally** on Saturday, May 23, 2009 at 4:57pm.

The lifetimes of lightbulbs of a particular type are normally distributed with a mean of 290 hours

and a standard deviation of 6 hours. What percentage of the bulbs have lifetimes that lie within 1

standard deviation to either side of the mean?

- Statistics -
**Ms. Sue**, Saturday, May 23, 2009 at 5:00pm
You're more likely to get help from an expert in this field if you use your **School **__Subject__ in the above box.

- Statistics -
**PsyDAG**, Sunday, May 24, 2009 at 12:28pm
Approximately 34% of scores lie between the mean and one standard deviation in any normal distribution. Therefore, μ ± 1 SD contains approximately 68% of the cases.

I hope this helps. Thanks for asking.

## Answer this Question

## Related Questions

- Statistics - The lifetimes of projector bulbs of a particular type are normally ...
- statistics - The lifetimes of light bulbs of a particular type are normally ...
- Statistics - The lifetimes of projector bulbs of a particular type are normally ...
- Ashworth college - The lifetimes of light bulbs of a particular type are ...
- statistics - A company produces batteries whose lifetimes are normally ...
- Statistics - The lifetimes of batteries produced by a firm are known to be ...
- Math - The batteries from a certain manufacturer have a mean lifetime of 890 ...
- Stats - The distribution of lifetimes for a particular brand of lightbulbs has ...
- sTATISTICS - If light bulbs have lives that are normally distributed with a mean...
- Probability Statistics - a manufacturing plant uses 3000 light bulbs whose ...

More Related Questions