In: Statistics and Probability
3. In a March 2020 Gallup Poll survey, 306 respondents either identified with or “leaned” toward the Republican Party. Among these Republicans, 92.8% approved of President Trump’s response to the coronavirus. In contrast, among the 302 respondents who either identified with or “leaned” toward the Democratic Party, only 29.5% approved of President Trump’s coronavirus response. Use these survey results to answer the questions below.
a) President Trump has claimed repeatedly that 95% of Republicans approve the job he is doing. Test the null hypothesis that 95% or more of Republicans approve of President Trump’s coronavirus response. Can you reject this null hypothesis at the 5% significance level? What about at the 1% significance level? [14 points]
b) Construct a 2-sided 95% confidence interval for the proportion of Republicans who approve of President Trump’s handling of the coronavirus situation. [12 points]
c) Test the null hypothesis that the proportion of Republicans who approve of President Trump’s handling of the coronavirus crisis is no greater than the proportion of Democrats who approve of President Trump’s handling of the crisis. Can you reject this null hypothesis at the 1% significance level? What about at the 0.1% significance level? [8 points]