Machine learning basics
Teaching a computer to sort each new case into one of a fixed set of groups, such as approve or reject, or real attack or false alarm.
Formal
A task in machine learning where the model learns from labelled examples to give each new input one label from a known, fixed list, often together with a score for how sure it is.
In plain English
Like a coin-sorting machine at a bank; every coin drops into the slot for its value, and there is no slot for a coin it has never seen.
In practice
At a shipping company, a model trained on thousands of invoices a bookkeeper had already sorted puts each new invoice into one of 40 cost types, such as fuel or harbour fees, and sends the unsure ones back to her.
Why it matters
No model sorts every case right, and wrong calls differ in cost (a missed attack usually costs more than a false alarm), so someone must decide which mistakes to accept and where a person checks.