Young people, ages 13-24, spend an average of μ = 22.2 hours a week online. Assume the time spent online has a normal distribution with a standard deviation of σ = 6.45 hours a week.
Question:
The amount of time spent on line by what fraction of young people fall within ±10 hours from the population mean?
a. 0.8264
b. 0.8576
c. 0.788
d. 0.9016