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