It is a requirement that you stay away from your home because of work or business. 'Work' means that you receive a salary or other remuneration for work that is performed for an employer/client.
'Business' means activity that is commercial in nature, e.g. sale and/or production of goods and services.
Studies are not regarded as work in this context. This means that if your studies are the main reason why you are living away from the parental home, you will not be classified as a commuter, even if you have a part-time job alongside your studies.
19-year old Anne from Fagernes has started studying in Oslo. She has a small bedsit in Oslo. She travels home to her parents every week, but she will still not be considered a commuter because the requirement is that her stays away from the parental home in Fagernes must be due to work.