We do not have “northern provinces”, those are territories.
For a less pedantic answer:
the territories are administered differently, with much more control from the Federal government
they have <120K in population which make statistical data difficult
they have very unique sociocultural circumstances (remoteness, high percentage of Inuit people, many “fly in” industries, etc) that make them hard to compare to the rest of Canada.
We do not have “northern provinces”, those are territories.
For a less pedantic answer: