The least squares method is a statistical technique used to find the best-fitting line or curve for a set of data points. It minimizes the sum of the squares of the differences between the observed values and the values predicted by the model. This approach is commonly used in regression analysis to estimate relationships between variables. By applying least squares, researchers can determine how well a model represents the data, allowing for predictions and insights. It is widely used in various fields, including economics, engineering, and social sciences, to analyze trends and make informed decisions based on data.