8.63 Consumer Outlook, continued Refer to Exercise 8.60. In a 2007 opinion poll, suppose that 430 adults identified those who thought mortgage rates would go up. The following question was posed: Do you think Bank of Canada may start hiking the base rate in coming years? Suppose that 390 who thought mortgage rates would go up and 100 of those who thought mortgage rates would not go up answered yes to this question.

a. Construct an 80% confidence interval for the differ- ence in the true proportion of Canadians regarding their opinion on Bank of Canada rate increases in the future.

b. Does the data indicate that there is a difference in true proportion in part a? Why or why not?