many diagnostic tests are indicative of problems only if a child scores

many diagnostic tests are indicative of problems only if a child scores in the upper 10 percent of those taking the test (i.e., at above the 90th percentile). Many of these tests are scaled to produce T score, with a mean of 50 and a standard deviation of 10. What would be the diagnostically meaningful cutoff in this case (i.e., at or above the upper 10 percent of scores)? Explain.