A report in 2010 indicates that Americans between the ages of 8 and 18 spend and average of µ = 7.5 hours per day using some sort of electronic device such as, smart phones, computers, or tablets. Assume that the distribution of times is normal with a standard deviation of Ó = 2.5 hours and find the following values.
a. What is the probability of selecting an individual who uses electronic devices more than 12 hours a day?
b. What proportion of 8- to 18-year old Americans spend between 5 to 10 hours per day using electronic devices? In symbols p(5 < X < 10) = ?