‘Probability’ examines how statistics deals with uncertainty. In probability calculus events are assigned a number between zero and one based on the degree of belief about their likelihood. Many theoretical interpretations of this calculus exist, but the underlying mathematics is the same. Several laws of probability exist, such as the Law of Large Numbers, conditional probability, and Bayes's rule. A sample is a subset of the whole population. As we cannot predict which values we will get in our sample, these are random variables. Cumulative probability distributions and probability density curves can predict the probability that we will pick a certain value. These curves have different shapes, described by parameters.