10 For a random sample of 1600 Canadians taken in January, 880 people indicate approval of the prime minister's performance. A similar poll a month later of a separate random sample of 1600 Canadians has a favorable rating by 944 people. Let x, denote the true proportion in January that approve of the prime minister's perfonnance, and let 2 repre- sent the true proportion in February.

a) Calculate point estimates of these proportions. Calculate the difference. and interpret

b) Construct a 99% confidence interval for .7 - 1. Interpret

c) Based on the interval in (b), explain why (i) there may have been no change in support (ii) if an increase in support occurred, it may have been fairly important. (iii) if a decrease in support occurred, it was probably so small as to be substantively unimportant.