The nonprofit organization behind the SAT college entrance exam has teamed up with a Silicon Valley pioneer in online education to make test preparation materials available for free starting Tuesday.

The move is aimed at making the college admissions race less stressful and more fair for students from poorer families.

The College Board gave unprecedented access to the revamped SAT it plans to introduce next spring to Khan Academy, which has developed diagnostic quizzes and interactive practice tests that will be accessible to anyone with Internet access. Khan Academy, based in Mountain View, is known for its free web-based library of instructional videos and academic exercises.

College Board President David Coleman said the partnership aims to level the college admissions playing field by putting high-quality training within easy reach of students without the funds for commercial test-prep services. Students who visit www.khanacademy.org/sat will find quizzes based on the math and reading sections of the new SAT scheduled to make its debut in March, as well as full-length practice tests written by the College Board.

Questions they answer incorrectly will show the specific skills they need to improve and offer step-by-step explanations for deriving the correct answer.

Nicole Hurd, founder of a nonprofit called College Advising Corps, said "I think they are really trying to change this from test preparation to an educational opportunity."

"If a young person takes the SAT math section, and they don't do well, instead of saying, 'Well, you don't do well,' it will push them back into the Khan curriculum so they can get the math skills they need so they are SAT-ready," she said.

The redesigned SAT will be graded on a 1,600-point scale last used in 2004 and will make the now-required essay section optional. Test-takers no longer will lose points for wrong answers.