Estimation theories are a set of specialized skills that involve predicting or approximating unknown values. It is an essential tool in decision-making, problem-solving, and risk management. Different estimation methods can be used depending on the context and available data. These methods can help to make informed decisions, minimize risk, and improve overall performance. Some commonly used estimation techniques include statistical analysis, expert judgment, historical data analysis, and simulation. Being proficient in estimation theories is crucial to ensure accurate and efficient decision-making.