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?© BrainMass Inc. brainmass.com December 20, 2018, 9:23 am ad1c9bdddf
Here is my answer:
According to the question, z=+/-1 for those that lie within 1 standard ...
For this solution, first we calculate the z scores. Then in the following step, we used z score based p value to calculate the probability.