Question: In a randomly selected sample of 400 registered voters in a community, 220 individuals say that they plan to vote for Candidate Y in the upcoming election.
a. Find the sample proportion planning to vote for Candidate Y.
b. Calculate the standard error of the sample proportion.
c. Find a 95% confidence interval for the proportion of the registered voter population who plan to vote for Candidate Y.
d. Find a 98% confidence interval for the proportion of the registered voter population who plan to vote for Candidate Y.