Split the Bill? When the time comes for a group of people eating together at a restaurant to pay their bill, sometimes they might agree to split the costs equally and other times will pay individually. If this decision were made in advance, would it affect what they order? Suppose that you'd like to do an experiment to address this question. The variables you will record are the type of payment (split or individual), sex of each person, number of items ordered, and the cost of each person's order. Identify which of these variables should be treated as explanatory and which as response. For each explanatory variable, indicate whether or not it should be randomly assigned.