According to the eMarketer, adults in the United States average 82 minutes per day on mobile devices in 2012. Assume that minutes per day on mobile devices follow the normal distribution and has a standard deviation of 27 minutes.
a. What is the probabilty that the amount of time spent today on mobile devices by a particular U.S. adult is.
1. Less than 70minutes?
2. More than 65 minutes?
3. Between 85 and $110 minutes?
b. Which number of minutes per day represents the 75th percentile.