Which statistical method is used to model the relationship between input and output variables for predicting continuous outcomes?

The chosen answer, regression, is indeed the appropriate statistical method for modeling the relationship between input and output variables, particularly when predicting continuous outcomes. Regression analysis allows practitioners to understand how the dependent variable (the outcome) changes in relation to one or more independent variables (inputs). This method is beneficial for forecasting, trend analysis, and determining causal relationships among variables.

In regression, a mathematical formula is established that best fits the observed data points. This relationship can be linear or nonlinear, depending on the nature of the data and the assumptions made in constructing the model. For instance, linear regression models the relationship using a straight line, while polynomial regression can capture more complex relationships by using polynomial equations.

In contrast, classification is focused on predicting categorical outcomes rather than continuous ones, making it unsuitable for this scenario. Clustering is primarily used for grouping similar data points without requiring defined outcome variables, and association looks for relationships between variables but does not involve prediction of outcomes. Thus, regression stands out as the correct choice for predicting continuous outcomes based on input variables.