Before the Presidential Debates, It Was Expected That the Percentages $\alpha$

Essay

Before the presidential debates, it was expected that the percentages of registered voters in favor of various candidates would be as follows. After the presidential debates, a random sample of 1200 voters showed that 540 favored the Democratic candidate; 480 were in favor of the Republican candidate; 40 were in favor of the Independent candidate, and 140 were undecided. We want to see if the proportion of voters has changed.
a.Compute the test statistic.
b.Use the p-value approach to test the hypotheses. Let $\alpha$ = .05.
c.Using the critical value approach, test the hypotheses. Let $\alpha$ = .05.