A certain brand of light bulb has a life, before burn-out that is normally distributed with a mean of 3000 hours and a standard deviation of 200 hours.
If one such light bulb is randomly selected and used in a warehouse where it will be left on continuously. What is the probability that it will last for at least 120 days (4 months)? Note: 120 days of continual use is 120*24=2880 hours.
Thank you so so much!! I didn't realize that is how to approach it...
So if six light bulbs are used in a warehouse where each light bulb would be left on continuously. What is the probability that more than half of the bulbs will last for at least 120 days? And the bulbs are independent of other bulbs?