Final answer:
The two major classes of quantitative business forecasting methods are time series forecasting and causal forecasting.
Step-by-step explanation:
The two major classes of quantitative business forecasting methods are time series forecasting and causal forecasting.
Time series forecasting involves analyzing historical data to identify patterns and trends and using them to predict future values. This method is used when the future values of a variable are influenced by its past values.
Causal forecasting involves identifying cause-and-effect relationships between variables and using them to predict future values. This method is used when the future values of a variable are influenced by other variables.