5.94 Earthquakes! Suppose that one out of every ten homeowners in the city of Kobe in western Japan has invested in earthquake insurance. If 15 homeowners are randomly chosen to be interviewed,

a. What is the probability that at least one has earth- quake insurance?

b. What is the probability that four or more have earth- quake insurance?

c. Within what limits would you expect the number of homeowners insured against earthquakes to fall?