What does "inferred" mean on a number?

An inferred number wasn't read directly. On a total, more than half of the stores behind it weren't read directly; on one store's value, that store's wasn't. It's marked so you can weigh it. A number with no marker was read at all or most of its stores. Coles, Woolworths and ALDI prices come from each chain's price zones and aren't marked; the page says so once.