20. A report in 2010 indicates that Americans between the ages of 8 and 18 spend an average of u=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 o=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 and 10 hours per day using electronic devices? In symbols, p(5