A poll was conducted by Ipsos Public Affairs for Global News. It was conducted between May 18 and May 20, 2016, with a sample of 1005 Canadians.

It was found 73% of the respondents “agree” that the Liberals should not make any changes to the country’s voting system without a national referendum first (http://globalnews.ca/news/). Find the approximate margin of error if the poll had been based on a sample of size

(a) n = 900,

(b) n = 1600, 

(c) n = 2500. 

Explain how the margin of error changes as n increases.