Final answer:
Using historical daily sales data to forecast inventory requirements is a time series forecasting technique.
Step-by-step explanation:
The given scenario, where a retailer uses daily sales of each product to identify patterns and forecast inventory requirements, is an example of a time series forecasting technique. Time series forecasting involves analyzing historical data and extracting patterns to make predictions about future values. By examining the repetitive patterns in the daily sales data, the retailer can estimate future inventory needs.