Newsweek conducted a poll in which respondents were asked if they "favor or oppose using federal tax dollars to fund medical research using stem cells obtained from human embryos." Of those polled, 481 were in favor, 401 were opposed, and 120 were unsure. Use a 0.01 significance level to test the claim that there is no difference between the proportions of those opposed and those in favor.
Use the sign test for the claim involving nominal data.