A sample of 100 mortgages approved during the current year showed that 31 were issued to a single-earner family or individual. The historical average is 25 percent.
(a) At the .05 level of significance in the right-tailed test, has the percentage of the single-earner or individual mortgages risen? Include a sketch of your decision rule as well as show all work.
(b) Is this a close decision?
(c) Describe any assumptions which are required