A random quantity between 1 and a pair of is a quantity chosen with equal likelihood from the set {1, 2}. For instance, rolling a good six-sided die and observing both a one or a two constitutes a random quantity between 1 and a pair of.
Random numbers between 1 and a pair of are elementary constructing blocks of likelihood and statistics, enabling numerous purposes, resembling modeling coin flips, performing simulations, and producing random samples. Their significance dates again to the seventeenth century when Pierre de Fermat and Blaise Pascal laid the groundwork for likelihood idea.