Ordinary Least Squares (OLS) is a statistical method used to find the best-fitting line through a set of data points. It works by minimizing the sum of the squares of the differences between the observed values and the values predicted by the line. This helps in understanding the relationship between variables, such as how income might affect spending. In practice, OLS is commonly used in regression analysis to make predictions and infer relationships. For example, a researcher might use OLS to analyze how factors like education level and age influence job satisfaction. By finding the optimal line, OLS provides valuable insights into these relationships.