Leading up to each Federal Election, the various opinion pollsters conduct nation-wide surveys of electors in an attempt to forecast the proportion of the electorate who will vote for each of the major parties. Suppose that a polling firm conducts a survey of 500 randomly selected electors, and their results indicate that 210 of these electors will vote for the ALP at the election.

Construct a 95% confidence interval for the (true) proportion of voters who will vote for the ALP at the election.