Distribution of times is normal with a standard deviation
A report in 2010 indicates that americns 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 0= 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<x<10)= ?
