Answer:
a) P=0.8
b) P=0.67
c) P=0.05
d) P=0.33
e) P=0.45
Step-by-step explanation:
a. What is the probability that the household has only a cell phone and has high-speed Internet?
This probability is stated in the question: "Suppose of U.S. households having only a cell phone, 80% have high-speed Internet", so the probability is P=0.8.
b. What is the probability that the household has only a cell phone or has high-speed Internet?
This probability is equal to the sum of the probability of having only a cell phone and the probability of having high-speed internet, less the probability of having both (to avoid counting this household twice).
c. What is the probability that the household has only a cell phone and does not have high-speed Internet?
This is equal to the probability of not having high-speed internet given that it has a cell phone (complementaty of the proability of Point (a)) multiplied by the probability of having a cell phone.
d. What is the probability that the household does not have just a cell phone and does not have high-speed Internet?
This probability is complementary of the one calculated in Point (c).
e. What is the probability that the household does not have just a cell phone and does have high-speed Internet?
This is equal to the probability of having high-speed internet less the probability it has both (cell phone and internet).