In October 2020, numerous political polls asked random samples of registered U.S. voters whether they support the candidacy of Joe Biden. Table 5 below gives information regarding five such polls. Table 5: Results of five polls, October 2020 Poll n % supporting Joe Biden candidacy 1 Reuters/Ipsos 951 44 2 Politico/Morning Consult 2021 51 3 Economist/YouGov 1231 50 4 Quinnipiac 1653 55 5 NPR/PBS/Marist 876 52 a. Which one of the five polls offers the most precise inference regarding the proportion of all registered U.S. voters supporting the candidacy of Joe Biden? (5 marks) b. Which of the five polls imply that more than half of the population of registered U.S. voters is in favor of Joe Biden? Use the critical value approach and assume that a = 0.01. (5 marks) c. Suppose that you decided to ignore polls with a margin of error larger than three percentage points (i.e., 0.030). Which of the five polls in Table 5 would you ignore? Assume that a = 0.05 and ensure you obtain three decimal places. (5 marks) d. Imagine you wanted to poll a random sample of registered U.S. voters so that the margin of error is only 1.5 percentage points. What is the minimum sample size achieving this objective, assuming that a = 0.01? (5 marks) e. Imagine instead you wanted to poll a random sample of Londoners about their support for the candidacy of Joe Biden, again so that the margin of error is only 1.5 percentage points. Given that London's population is much smaller than the number of registered U.S. voters, what is now the appropriate minimum sample size achieving this objective, assuming that a = 0.01