In a lecture, students tend to only partially listen and are easily bored with what the lecturer has to say. In a group work situation, one is able to keep focused because they get to interact with the other students. It is also a lot harder to get bored in a group discussion because everyone usually has a different interesting point to share. Overall, I believe that group work is more beneficial to student than a lecture is. They are both good learning sources, but I feel that group work is a much more effective source of learning.
Lectures tend to be boring and one-sided.
The teacher or professor talks the entire time and the students just sit there and listen. But, when you work in groups you get to interact with other students and get their opinions on the work. In groups, the students get to help each other out. It is much easier for me to learn from another student than a teacher.