Grouping students into seven academic disciplines, the study shows wide differences in the number of hours they put into schoolwork outside the classroom. Among students concentrating in engineering, 42 percent say they spend at least 20 hours per week on such study, well ahead of any other group.
They are followed, in descending order, by students studying physical sciences, biological sciences, arts and humanities, education and social sciences. Business majors ranked last, with 19 percent saying they spend 20 hours or more each week on schoolwork.
via nytimes.com
Note: I'm saying this as a BS business and BA history double major.