Even though there may be a deceiver of some sort, very powerful and very tricky, who bends all his efforts to keep me perpetually deceived, there can be no slightest doubt that I exist, since he deceives me; and let him deceive me as much as he will, he can never make me be nothing as long as I think I am something. Thus, after having thought well on this matter, and after examining all things with care, I must finally conclude and maintain that this proposition: I am, I exist, is necessarily true every time that I pronounce it or conceive it in my mind.
The corresponding percentile of each scaled score varies from test to test—for example, in 2003, a scaled score of 800 in both sections of the SAT Reasoning Test corresponded to a percentile of , while a scaled score of 800 in the SAT Physics Test corresponded to the 94th percentile. The differences in what scores mean with regard to percentiles are due to the content of the exam and the caliber of students choosing to take each exam. Subject Tests are subject to intensive study (often in the form of an AP , which is relatively more difficult), and only those who know they will perform well tend to take these tests, creating a skewed distribution of scores.