Take your scaled score with a grain of salt. Your scaled score is based on a "curve"; it is obtained by comparing your raw score (the number of questions you answered correctly; of the 120 questions, only 100 count in your score) with the performance of students comprising a norm group. This method is used in order to negate the differences in administering the MAT and the multiple forms of the test. Scaled scores range from 200 to 600, with 400 being the mean score.
Compare your percentile score with those intending your same major. The Percentile for Intended Major ranges from 1 to 99 and represents the percentage of examinees from the norm group who intend to take the same major and who scored less than you did. This score will give you (and admissions departments) a clearer idea of your knowledge than your scaled score.
Rank yourself against all test takers. The Percentile for the Total Group also ranges from 1 to 99 and represents the percentage of all examinees who scored less than you did in the complete norm group. There are no "passing" scores on the MAT, only comparative scores, so your percentile scores will most accurately reflect your knowledge compared to your peers.