Answer:
Psychometric.
Step-by-step explanation:
Psychometrics is part of psychology that has to do with various kinds of measurements when it comes to human development and psyche. In this case, Julie wants to see what the achievement levels of middle school students are, and in order to do that, she will use psychometric approach. This approach will be the best here because it deals with measuring skills, levels, personality traits, etc. through tests and questionnaires.