Describe the structure of a graph as used in an Artificial Intelligence (AI) system.

Mark scheme

Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.

1. MP1 A graph uses vertices/nodes to identify/represent entities such as destinations, people, etc
2. MP2 Edges are used to connect nodes and can represent possible paths between them // a path is the list of nodes connected by edges between two given nodes
3. MP3 Nodes/edges can be labelled/weighted, and this is a weighting that can be applied and used in the context of the application
4. MP4 A cycle is a list of nodes that return to the same node.
5. MP1 Supervised learning uses labelled data // Unsupervised learning makes use of unlabelled data.
6. MP2 Labelled data means that known outcomes are applied to specific inputs to help the AI predict outcomes.
7. MP3 Supervised learning requires initial human input/training // Unsupervised learning does not require human input/training.
8. MP4 With unlabelled data in unsupervised learning, outcomes are not known
9. MP5 ... the AI has to search for hidden patterns/structures/clusters
10. MP6 ... within the data in order to predict outcomes.