Looked in the textbook and having a hard time understanding how to correctly apply the formulas to this type of question. Textbook examples reads as the following.
Television viewing reached a new high when the global information and measurement company reported a mean daily viewing time of 8.35 hours per household. Use a normal probability distribution with a standard deviation of 2.5 hours to answer the following questions about daily television viewing per household.
a. What is the probability that a household views television between 6 and 10 hours a day (to 4 decimals)?
b. How many hours of television viewing must a household have in order to be in the top 8% of all television viewing households (to 2 decimals)? hours
c. What is the probability that a household views television more than 4 hours a day (to 4 decimals)?