In an election held last year that was contested by three parties, party X captured 31% of the vote, party Y garnered 51% and party Z received the remaining votes. A survey of 1,200 voters asked each to identify the party that they would vote in the next election, and the survey result revealed that 408, 571 and 221 would vote for party X, Y and Z, respectively, in the next election.

Can we infer at the 5% significance level that voter support has changed since the election? Please show all step! Thanks