Odds are used to describe the chance of an event occurring. The odds in favor - the ratio of the number of ways that an outcome can occur compared to Plots and Box-and-Whiskers Plot Pre-Algebra Probability and statistic: Calculating the. Convert A to B odds for winning or losing to probability percentage values for both winning and losing. Probability and odds are two basic statistic terms to describe the likeliness that an event will occur. They are often used interchangeably in.