A random variable gives each outcome of a sample space a number, and its probability distribution can be graphed like a data set. Probabilities come from the sample space when every outcome is equally likely, or from a tally when they are not. The expected value, each value times its probability added up, is the mean of the distribution, and it weighs a decision. Equal probabilities make a draw fair, and a two-way table shows what a check that flags bikes really tells you. The crew runs Race Day on all of it.