Two students recently took algebra class tests. the students are at different schools but wanted to compare their performance. the first student scored 80 on the test. her class average was 90 with a standard deviation of 10. the second student scored 70. her class average was 50 with a standard deviation of 10. which student did better?

On the reasonable assumption that doing better means something like, did better relative to the other students in her school, the second student did better. The first student did somewhat worse than most of the students at her school -- if the scores fit a normal distribution then 85% outscored her. The second student, on the other hand, did better than almost all of the students at her school -- if the scores fit a normal distribution then she did better than 95% of her peers.

The scale factor of what ?