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.

Question

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.

Quizplus · Accepted Answer

The Answer of 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.

Before the Presidential Debates, It Was Expected That the Percentages α\alphaα

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