A report from 2010 indicates that Americans between the ages of 8 and 18 spend an average of = 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= 2.5 hoursand find the following values.

What proportion of 8- to 18-year-old Americans spend between 5 and 10 hours per day using electronic devices?