To determine what students at a school would be willing to do to help address global warming, researchers take a random sample of 100 students. The students answer the questions, "How high of a tax would you be willing to add to gasoline (per gallon) in order to encourage drivers to drive less or to drive more fuel-efficient cars?" and, "Do you believe (yes or no) that global warming is a serious issue that requires immediate action?" The researchers want to compare the mean response on gasoline taxes (the first question) for those who answer yes and for those who answer no to the second question.