Assignment:
According to the Sleep Foundation, the average night's sleep is 6.8 hours (Fortune, March 20, 2012). Assume the standard deviation is .5 hours and that the probability distribution is normal.
- What is the probability that a randomly selected person sleeps more than 8 hours (to 4 decimals)?
- What is the probability that a randomly selected person sleeps 6 hours or less (to 4 decimals)?
- Doctors suggest getting between 7 and 9 hours of sleep each night. What percentage of the population gets this much sleep (to the nearest whole number)?