A city commissioner claims that 80% of the people living in the city favor garbage ...

  

A city commissioner claims that 80% of the people living in the city favor garbage collection by contract to a private company over collection by city employees. To test the commissioner’s claim, 25 city residents are randomly selected, yielding 22 who prefer contracting to a private company.

a) If the commissioner’s claim is correct, what is the probability that the sample would contain at least 22 who prefer contracting to a private company?

b) If the commissioner’s claim is correct, what is the probability that exactly 22 would prefer contracting to a private company?

c) Based on observing 22 in a sample of size 25 who prefer contracting to a private company, what do you conclude about the commissioner’s claim that 80% of city residents prefer contracting to a private company?