Math tutor is evading or giving wrong answers I am a student in a german technical college. We have several tutors for our various math subjects. One of those tutors is not a student but an employee of the college. He offers an open hour where students can ask question about all the math subjects. I will refer to him/her as X.

During the preparation for my exams I asked X 2-3 questions and later after I understood most of the subjects material was present when he answered other's students questions. This is when I noticed that X sometimes evaded clear answers or just gave plain wrong answers. This became especially obvious after I had understood the subject myself. Here are some examples:



Question 1: What is meaning of the probability density function?  What does it describe? I know it's the derivative of the cumulative distribution function and I understand the cumulative function but what can I do with the density function?

X: It's just the derivative. That's all you need to know.

Student: But, I mean what can I do with it? Why am I learning it?

X: It's really just the derivative, it has no other important meaning. You don't need to know more.

Student: Well....OK.



Question 2: I still don't understand how to read a correlation out of a scatter-plot. For example this one? How do I know if the variables are correlated?

X: You can't really learn this, it's just a matter of practice. You have to do it for years.



There were other question where X simply gave a blatantly wrong answer (I can't remember specific examples). For me it is clear that X simply does not know the answers and instead of admitting it and offering to look it up X simply gives a harsh answer to intimidate the students. The tutorial is mostly visited by students who are struggling to understand the basic stuff. The other good students did not bother coming to the tutorial so they never saw X do that. I came for some advanced questions and this was when I noticed the wrong answers. I assume that X does help students with other areas of math where X knows more.

I think X's behavior is unacceptable because X is hindering the education of the students and even confusing them. Because most of the question had simple answers.

I have two questions now:


How do I tell this to the responsible professor? I guess it won't be easy for him because he would have to investigate this matter and in the worst case it could lead to firing X and he probably does not want to go though all the trouble.
When do I tell the professor? I am interested in this subject myself and volunteered to be a tutor next semester. I probably won't work with X because X gives a general tutorial for different areas of math. Coming up with this matter during my "interview" would probably be a bad idea. I think it's probably better to first become tutor and "gather more intelligence" until telling the professor. I will probably be also more credible then.


Would love to hear your ideas about this matter.
I don't know about German technical colleges, but in the US and in Switzerland, students do have a chance to give feedback about the teaching. This sort of information is very useful then! It has the benefit of usually being anonymous. But when you do give this information, make sure that it is factual and detailed (so something like what you wrote in the question) so that the professor has a point of entry for the investigation. 

If I have an assistant who behaves exactly as you described, I would be very unhappy with the assistant and will be thankful for any student who brings it to my attention. 

Now, to answer your specific questions:


How to tell the professor

a. Again, I don't know about the German system. But if you don't want to be confrontational there are often options of bringing this up through the student union or the association of mathematics/statistics students. In some universities there are also student advocates who can act as intermediary for you.

You also mentioned that other "better students" don't know about this. Perhaps you should drag some of your friends to the office hours and show them what is going on. You will get a sanity check on whether your impression is correct and perhaps have more voices to join you in complaining. 

b.  Documentation is important. You don't want this to be a case of "whom do we trust more." If you feel sufficiently strongly about this, get the assistant's answers either recorded (audio-visual) or in (his/her) writing. If the assistant also answers queries by e-mail that's one way to provide documentation. 

c. Be factual, do not exaggerate. When I answer students' questions, sometimes I would deliberately give answers which, from the point of view of an expert, is incomplete. These can be pedagogical decisions made to guide a student's focus in his or her studies. While I am not claiming that your tutor is doing precisely that, it is important you present his/her answers exactly as they are, and not "interpreted by you."

d. Another option is to make this about the system, and not the individual. You say that the tutor has open office hours during which he/she answers questions from all subjects. Maybe that is the problem! Propose to your professor(s) that it may be more efficient to have tutors divided up by specialty and answer questions in those fields only. (At my current institution we have precisely a system set-up so that tutors will not be answering questions out of their expertise.) 
When to tell the professor

As early as you feel comfortable. If I am in charge of tutors, this would be something I want to find out sooner rather than later.