statistics

Question 17 122 3 pts ements The lifetimes of projector bulbs of a particular type are normally distributed with a mean of 470 hours and a standard deviation of 15 hours. Apply the 68-95-99.7 rule to answer what percentage of the bulbs has lifetimes that lie within 1 standard deviation of the mean on either side? 99% O 95% 50% O 68% Question 18 3 pts The amount of Jen's monthly electric bill is normally distributed with a mean of $160 and a standard deviation of $14. Fill in the blanks by applying the 68-95-99.7 rule. The middle 68% of her electric bills are between $ and $