Unobserved are the trips to the store and the cooking and eating and the inspections of the larder. Maybe these can be discriminated usefully, but maybe they should be lumped into consumption. Other unobserved events include purchases from the competitors. When a person purchases a freezer, his status changes to that of a freezer owner and that fact will persist. The event of acquiring a freezer is more common than of giving up the possession of a freezer.
People have preferences among states of affairs, more specifically, among objects.
Distributions of properties over people. The customers have age, sex, income, and ethnic distributions. Customers appear and disappear. There are causes for the appearance and disappearance of customers, and supermarket chains will be interested in finding them. These include moving in or out of the area, changes in family circumstances, advertising campaigns by the chain or its competitors, changes in the store or its hours of operation, satisfaction or dissatisfaction with goods, prices, or service.