The federal government is currently trying to devise plans to help homeowners who owe more on their mortgages than their houses are worth. A new survey estimates that 33% or those holding “underwater” mortgages would be helped by the current plan.
a. In samples of mortgages of size 75, what proportion of the samples would you expect to produce sample proportions equal to or larger than 0.25?
b. If a sample of size 75 produced a sample proportion of 0.45, what would you infer that the population proportion of mortgages “underwater” really is?
c. In a sample of 90 mortgages, what would the probability be that the number of mortgages “underwater” would be between 25 and 35?