A CDF, or Cumulative Distribution Function, is a statistical tool that describes the probability that a random variable will take a value less than or equal to a specific number. It provides a complete picture of the distribution of probabilities for a given dataset, allowing for the analysis of how values are spread out. CDFs are commonly used in various fields, including statistics, finance, and engineering, to model and understand uncertainties. By plotting a CDF, one can visualize the likelihood of different outcomes, making it easier to interpret data and make informed decisions based on probability.