In a survey on corporate ethics, a poll split a sample at random, asking 538 faculty and corporate recruiters the question: “Generally speaking, do you believe that MBAs are more or less aware of ethical issues in business today than five years ago?” The other half were asked: “Generally speaking, do you believe that MBAs are less or more aware of ethical issues in business today than five years ago?” These may seem like the same questions, but sometimes the order of the choices matters. In response to the first question, 53% thought MBA graduates were more aware of ethical issues, but when the question was phrased differently, this proportion dropped to 44%.
a) What kind of bias may be present here?
b) Each group consisted of 538 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 faculty and corporate recruiters that believe MBAs are more aware of ethical issues today?
c) How does the margin of error based on this pooled sample compare with the margins of error from the separate groups? Why?