We want to estimate by survey the proportion p of voters who are in favor of the

maintenance of Justin Trudeau at the head of the government. For that, we would like

construct a symmetric confidence interval for p of confidence level

0.90.

(a) What sample size should you choose so that the error is at

more 0.02?

(b) If in a sample of size n = 1200, 360 people are in favor of

Justin Trudeau, find a confidence interval with a threshold of 5%

to check if the proportion of Canadians in favor of Justin Trudeau

is less than 40%.