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. (a) Identify the response variable and the explanatory variable. (i) What is the response variable? The amount of tax the student is willing to add to a gallon of gasoline. Whether the person in the sample is a student at your school or not. Whether the student believes that global warming is a serious issue or not. The fuel efficiency of the cars. (ii) What is the explanatory variable? The amount of tax the student is willing to add to a gallon of gasoline. Whether the person in the sample is a student at your school or not. The fuel efficiency of the cars. Whether the student believes that global warming is a serious issue or not. (b) If you were to construct a 95% confidence interval to compare the two groups, what would statistical method could be used? Select the most appropriate one. two-sample t test paired-t test