다음은 IRS 홈페이지 http://www.irs.gov/publications/p519/ch08.html#d0e9609
에서 찾은 글입니다.

지금 일하고 있는 곳이 작은 사무실이라
제가 이런것도 찾아서 사장님께 보여드려야 하는 상황입니다.
이것만 보여드려도 세금감면을 받을 수 있을지 궁금합니다.
가장 마지막 줄에 practical training 을 포함하고 있으니
충분한 근거가 될것도 같습니다만
아시는 분들 답변 부탁드립니다.

Students and Exchange Visitors

Generally, services performed by you as a nonresident alien temporarily in the United States as a nonimmigrant under subparagraph (F), (J), (M), or (Q) of section 101(a)(15) of the Immigration and Nationality Act are not covered under the social security program if the services are performed to carry out the purpose for which you were admitted to the United States. This means that there will be no withholding of social security or Medicare taxes from the pay you receive for these services. These types of services are very limited, and generally include only on-campus work, practical training, and economic hardship employment.