It is reported that 21% of American households use a cell phone exclusively for their telephone service. In a sample of eight households, find the probability that:
a. No household uses a cell phone as their exclusive telephone service. (Round your answer to 4 decimal places.)
b. Exactly 2 households exclusively use a cell phone for telephone service. (Round your answer to 4 decimal places.)
c. Find the mean number of households exclusively using cell phones. (Round your answer to 4 decimal places.)