For student appearing for any examination & especially in case of maths they fear,sometimes worries & tension , & in certain cases students experience one can of phobia with creates tension & worries .
For such atmosphere of students , parents especially father should become his guideline ,behaviouring in the manner has friend. Even good teachers remain an observer just as friend of such student offer them all the necessary tips , guidance under a friendly approach
Why not take a normal anxiety scale and give it just before an examination and a time after the examination then you see the difference. E.g. Beck's anxiety scale (BAI).