We had a group project that involved 4 people. 3 of us worked really hard. Personally, I feel I did about 1/2 the work. We had a Viva at the end of the project. I got nervous and did quite badly. When the grades were out I got a B, same as the guy who didn't really do much. I'm wondering if it's a good idea to ask the professor to consider re-evaluating my grade.
It is a good idea to ask. But you probably won't get a change in grade.
The "ask", however, should be about why the grade is lower than you thought it should be. Learn, if you don't already know, what the grading criteria was and how much each element contributed. The professor should be able and willing to answer these sorts of questions.
But it should also have been clear before the project started what the grading criteria should be and how important would be the evaluation of each part. It is possible that half the grade was assigned on the presentation.
Learning what happened gives you the chance to work on those things in which you were judged lower than the others. That is the real reason for asking.
If you really want the grade changed then get your teammates to advocate for it based on your contribution to the other part. But that will have to come from them, not just your claim of doing "half".
Sounds like you probably got a good grade for the project work and your poor presentation performance dragged your final result down.
Your colleague may have a poor project grade but the presentation grade pulled him up...
Without the detail of exactly what was required, the marking scheme and the precise results, not much more can be said.
You can choose to chase this, or not, but I don’t think you have a big problem here.
One aspect of group projects that students sometime overlook, is that work is sometime set as a group activity so that students can experience group activity and team working and also be assessed on how they perform as a group.
Many employment (and research) tasks take place in groups and learning to work in and then being judged as a group is something that needs working on as part of the educational process. It is often something that employers and professional bodies expect degree courses to include.
Going through the stages of group development often has to be experienced. (Tuckman, 1965)
So how team members interact and perform in total is often as important as what an individual contributes. I try to explain to my students that when one feels strongly that their personal contribution has been overlooked that this is an indication that they have not fully embraced the teamworking dynamic and should be focussing on the final deliverable and not their individual fraction. This might be the feedback you get if you asked for a re-grade. Asking for a re-grade could just be confirmation that you were not fully cognizant of the grading criteria.
Without knowing about the details of the assessment scheme we cannot know what factors were taken into account to form an individual's grade, but I suspect it is more than just an individual's labour.
The thing with group projects in a classroom setting is that nobody is particularly glad to be in them. Group projects are just something that need to be done sometimes to grow as a person. However, the best advice I have heard about working as a group is that you need to take responsibility for the outcome of your group. If your group does bad, so do you. If a teammate is lagging, so do you. If everyone is performing at their best, so do you. While you might have gotten a lower grade, you just need to reflect on what you could have done to be better and how you could have brought your team along with you. Groups will always have weak members, but if you’re part of the group then you share in both the fruits and spoils of the group.