Death penalty poll, part III. In the chapter s example and again in Exercise 21 we looked at a Gallup Poll investigating the public s attitude toward the death penalty. In response to one question, 60% thought it was fair, but when the question was phrased differently, the proportion in favor dropped to 54%.

a) What kind of bias may be present here?

b) Each group consisted of 510 respondents. If we combine them, considering the overall group to be one larger random sample, what is a 95% confidence interval for the proportion of the general public that thinks the death penalty is being fairly applied?

c) How does the margin of error based on this pooled sample compare with the margins of error from the separate groups? Why?