Ineed in statistic it's very confusing

What properties allow transformation to be used as a problem solving tool

For which pair of functions is (gof)(a)=|a|-2?

Reading tests are compared for two students. sara got 98, 100, 65, 78, 98, 46, 100, 100, 45, and 50 on her reading test. lee got 97, 67, 89, 99, 100, 45, 79, 89, 58, and 67 on his reading test.