<span>This may be due to the fact that many intelligence tests are designed to measure the person's previous knowledge, and not the real intelligence, so Juan may have different knowledge than those required by the test. In addition, the difference of the language can also affect the performance and score of Juan and the lack of experience performing this type of tests.
<span>Their admission to the university is affected because the universities require high scores in these tests as an admission requirement. I hope my answer can help you. </span></span>
Juan is most likely dealing with lots of issues and stress points that his classmates don't have to face, resulting in less time to prepare for things like the SATs and lower confidence levels. Since his parents immigrated to the US less than 5 years ago, and Juan is old enough to be taking the SATs, we can infer that Juan grew up in Mexico. Not only does he probably encounter cultural and linguistic differences that make it difficult for him to succeed on standardized tests in the US, but also his position as the firstborn most likely adds pressure to helping his parents with things like working and maintaining a household, rather than studying and preparing for college.
