Probability distributions are mathematical functions that describe the likelihood of a random variable taking on different values. They are used to model uncertainty and variability in a wide range of fields, including statistics, finance, and engineering. Common types of probability distributions include the normal distribution, which is commonly used to model data that is symmetric and bell-shaped, and the binomial distribution, which is used to model the number of successes in a fixed number of independent trials. Understanding and using probability distributions is essential for making informed decisions and drawing meaningful conclusions from data.