What are strategies for minimizing student questions during exams? Context: I am an assistant professor of mathematics at a small liberal arts college in the US.

I generally find student questions during tests and quizzes to be somewhat annoying.  I disliked them when I was a student, and they're even worse as an instructor.

To elaborate on my dislike:

As a student I found such questioning very distracting.  I'd be in the midst of trying to solve a difficult problem when suddenly people around me are talking in hushed voices about a problem I had already done.  As one can imagine, it was challenging to pull my attention back to what I was doing.  

As an instructor, I want to do my best to provide a good test environment, so I would like to minimize questions that I see mostly as a distraction.  In addition, most courses contain a student or two who I don't entirely trust, so I like to be able to watch the students during the exam to ensure test security, and answering questions can hinder that.  I also don't want students getting up during a test to ask questions, for obvious security-related reasons.  (This problem is easily solved by telling them to raise their hand.)

Most questions fall into the following categories:


Legitimate questions aiming to clarify vague instructions or a typo.
Questions fishing for a hint.
Questions seeking support of a solution method.
Questions asking for confirmation about answer format.


Type 1 questions are not a problem. Type 2 and 3 questions are foolish, because I hardly ever tell students anything remotely useful. Type 4 questions are irritating, because my questions specifically say what format to use (i.e. "show two decimal places," "you do not need to simplify," etc.).

What are some strategies for eliminating questions of type 2, 3, and 4 while not discouraging type 1 questions?

Of course, I can just straight-up tell them that they're not to ask questions unless they believe them to be very legitimate, but I'd like to use a less "adversarial" approach, if possible.
I explain at the start of the first test that, "Questions clarifying what you're reading are okay (raise your hand, I'll come over). I cannot tell you how to solve a problem. My response may be, 'I can't tell you that during the test.'"

If Question #1 comes up, I do as stated. Questions #2-3 get a fairly loud (but polite) repetition of, "I can't tell you that during the test." (Or, "That's what you're being tested on."). Question #4 may get, "Just read the direction carefully" (which itself is a repetition of something I need to say during almost every single class meeting). 

I find this public act tamps down on questions as much as I can hope for. The main thing is to be solidly consistent. Counterexample: I was co-proctoring with another professor in their class. That professor got a question, shook his head in disgust, muttered "You should know that", and walked away. Then turned around, walked back, and actually did talk the student through how to solve the problem. This can only encourage more fishing questions like that. 

Due diligence: In liberal-arts math courses I have occasionally had students express disbelief and/or outrage that I wouldn't help them during a test. "But you're the teacher, that's your job" kind of thing.