# Mean and Standard Deviation of Light Bulb Lifetime

The lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 5 hours. What percentage of bulbs has lifetimes that lie within 1 standard deviation of the mean on either side?

Â© BrainMass Inc. brainmass.com March 4, 2021, 11:53 pm ad1c9bdddfhttps://brainmass.com/statistics/dispersion-and-spread-of-data/mean-standard-deviation-light-bulb-lifetime-463719

#### Solution Summary

The solution determines what percentage of bulbs has lifetimes that lie within 1 standard deviation of the mean on either side.

$2.49