I agree with @MotherOfDragons . Why is everyone quick to assume that the folder was given to the other student by the professor? Either way, there’s a issue that needs to be addressed with the professor. If he willingly gave the folder to the classmate, that’s a problem or if he did not secure the folders well enough that the student had access to her classmates folder , that is also a problem. Ultimately, the professor is responsible , and should at least be made aware of the issue so other compromises in privacy are avoided.
But these are two lab partners. They are supposed to be working together. It seems as if we are only getting half of the story here, and it would be helpful if OP would come back and clarify (including an explanation of how she knows her lab partner’s grades).
I don’t think it’s important to know how the OP knows (or doesn’tknow) his/her partners grades or if it’s even fully accurate that it’s the lowest. I’m sure as a partner s/he has a reasonable idea of what type of student the partner is. And what type of student the partner is is pretty irrelevant anyway (except perhaps that part where she is known for cheating).
The OP is not comfortable with the situation and should speak to the professor.
I think that your lab partner has more to worry about from you than you do from her. You seem to be unnecessarily competitive and suspicious to me and your remarks about her grades make it sound like you know a bit too much about her performance in the class. As lab partners you should be working as a team but your ill will toward her makes it sound like she needs to watch her back.
Speak to the professor if you insist but personally, I don’t think that conversation will end up reflecting well on you.
In OP’s other thread she acknowledges allowing one of her three lab partners copy her labs: “I let her copy lab assignments since she’s my lab partner. The professor told us we must help our group members out with lab assignments.”
Obviously it’s unclear whether the offending person in this thread is the lab partner that she helped in the other thread. In any event, it doesn’t seem that the professor is at fault here, although OP indicates he is “lazy” in the other thread.
Lab partners generate data together; they are supposed to write up the results on their own, so I agree she had no business looking at it (if that’s what she actually did). Unfortunately, many professors are not always as FERPA-aware as they should be. The most likely scenario is that he didn’t think before he handed the folder to Susie, who said “oh, I can give Mary hers too – I’m just about to go meet her.” He might have felt that a graded lab report wouldn’t give any sort of advantage and that your grade was good, so it wouldn’t be embarrassing (old school thinking – not defending it). Did he violate FERPA? – yes, but it is not in your best interest to go in accusatory. The best approach would be to go the professor and say “in the future, please don’t give my work to Susie. We’re not really close and I’m a little uncomfortable with her having my work.” He’ll likely think “whoops, shouldn’t have done that” and not do it again.
If he does it repeatedly, post again and I’ll give you some advice about escalating (after you finish his course). The occasional old-timer (not necessarily old, but started out more than 10-15 years ago) can be a little dense about these issues (often in the “we have an honor code and I have the right to trust my students not to peek at grades or otherwise act dishonorably” category). Those folks generally need a lecture from their department chair.