Question

The amount of time a certain brand of light bulb lasts is normally distributed with a
mean of 800 hours and a standard deviation of 50 hours. what is the probability that
a randomly chosen light bulb will last between 780 hours and 810 hours, to the
nearest thousandth?

Answer 1

Answer:

23.47 %      ( or .2347)

Step-by-step explanation:

780    is    20/50 = .4   for z score - .4

810     is    10/50 = .2       z-score = .2

 Use z-score table         .5793 - .3446 = .2347     23.47%