Ola Nordmann is a national personification of Norwegians, either for individuals or collectively.
Caricatures of Ola Nordmann as a national personification of Norway usually depict him as a blond-haired man dressed in bunad-like traditional folk clothing and wearing a woollen red top cap - the traditional headwear of a Norwegian gnome or nisse.
In the romantic national period, the farmer often came to represent the Norwegian people as a whole, hence the representation.
Ola Nordmann is also used as a default name in examples used to guide people in how to fill in forms etc.
(similar to Joe Bloggs in the UK or John Doe in America).