Let's say that the standardized test had 100 possible points. If we wanted to identify the top 25%, why not just select those with raw scores above 75?
Why do we have to standardize the scores?
I answered this previously.
We need to get 25% of the obtained scores. You are assuming that the scores ranged close to 1-100. That is typically NOT the case. What if all the scores were above 75?
Check with one of the tests taken in any of your classes. What would the range be? Certainly it would not be the whole possible range of points.