All businesses must do some aspect of planning - whether it's a bank trying to determine how many loans to process each month, or Apple, trying to determine how many iphone 13s to make in Apr, May, and June. In either scenario, planners use the forecast for the product or service, as the most important factor - sometime this forecast is developed by marketing or sales, and other times, it is simply generated by a system, looking at sales history. Different businesses/planners will refer to the forecast, as forecast, demand, or sales, - it all means the same thing - it's the quantity per time period that the market needs. Regardless, planners have 2 basic approaches to planning the production 1) they can opt to plan a 'level' (same) number of units per time period, or they can 'chase' (match) the forecast. Additionally, managers can dictate a specific quantity of ending inventory, that must be left over, after planning to meet the forecast. So if the total forecast for 4 months is 1200, and there is a requirement to have an ending inventory of 400, then the planner must plan for 1600, across the 4 months. The reasoning for such