Are the prepositions at, in, on interchangeable here? If yes, do they all mean the same?
I have student-teaching experience at/in/on (all) high school levels.
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
I think at is your best choice; that's the preposition usually used in that context.
More specifically, I would use at, because we usually say at all levels:
I have student-teaching experience at the high school level.
It may be worth noting that, at least in the U.S. educational system, all of high school is considered one level, consisting of four grades. So, this is the way I'd recommend saying this (depending on what grades you taught):
I have student-teaching experience at the high school level. [i.e., I taught students in grades 9 - 12]
I have student-teaching experience in all high school grades. [i.e., students in grades 9, 10, 11 & 12]
I have student-teaching experience at both the high school and middle school level. [i.e., students in grades 9 - 12, as well as students in grades 6 - 8]
However, that might be different in other countries.
One other thing worth mentioning: when we use a past tense verb with the phrase "in high school," that usually indicates an activity we did as a student.
I took geometry in high school.
So, I would avoid, "I had my student-teaching experience in Chattanooga High School" (even though it's not grammatically incorrect), because that could be interpreted to mean that you did student teaching while you were a high school student. It would be much better to say:
I had my student-teaching experience at Chattanooga High School.