Q1) If light bulbs have lives that are normally distributed with a mean of 2500 hours and a standard deviation of 500 hours, what percentage of light bulbs have a life less than 2500 hours?
Q2) 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
Q3) The amount of Jen s monthly phone bill is normally distributed with a mean of $60 and a standard deviation of $12. Fill in the blanks:
68% of her phone bills are between $______________ and $______________.