When it comes to sampling methods, random sampling is one of the most effective. The principal wants the results of his or her sample to be as fair as possible, so it is best to choose students randomly, and in a neutral environment. The mall is not a neutral environment because not all students have access to the mall, and even those who do are not guaranteed to provide accurate results. The same goes for a basketball game, and student council. Samples taken from these environments are likely to produce more bias. However, collecting a survey from every tenth student entering the school one morning is more likely to produce accurate results that are representative of the school population.