What is the difference between open and closed questions? What is the difference between the mean and the median? What is the difference between correlation and causation? How do you decide whether a website is an acceptable source for a report? Why do you need to know the exact way a question was phrased before using results from the study as evidence? Why should you test a questionnaire with a small group of people before you distribute it?Why should you look for alternate explanations for your findings?