One advantage of having the students work in groups is that when a student asks a question it implies that nobody in his group knows the answer - he's not the only one. Now there are always tradeoffs, of course, to whatever methods are used to teach classes. Most students come to class with a reasonably good start on the day's material. They may not have all the answers but they typically have a pretty good idea of where they need help. Students are directly participating in the development of the class results.
Students have ample opportunity to ask questions of their group and the instructor.
The instructor gets detailed information on how well the students are understanding the material by how well they're doing the investigations. And so the instructor gets detailed information on what needs improving. Class time invariably goes quickly. And with a good mix of students the classes can be particularly lively and enjoyable. ECE 109, ECE 207 and ECE 209 is follow each of the three class meetings with an hour of lab.