A little more than a year earlier than the survey described in Exercise 6.42, in February 2010, a different survey of 15,000 American adults found that 35.1% identified as Democrats and 32.1% identified as Republicans, with the rest identifying as independent or other. Answer the same questions about these survey results as in Exercise 6.42: If we want 95% confidence, what is the margin of error in the estimate for the proportion of Democrats? For the proportion of Republicans? Do you feel comfortable concluding that in February 2010 more American adults self-identified as Democrats than self-identified as Republicans? Explain.

Exercise 6.42

A survey of 15,000 American adults in March 2011 found that 35.3% identify as Democrats and 34.0% identify as Republicans, with the rest identifying as independent or other. If we want 95% confidence, what is the margin of error in the estimate for the proportion of Democrats? For the proportion of Republicans? Do you feel comfortable concluding that in March 2011 more American adults self-identified as Democrats than self-identified as Republicans? Explain.