The 84th percentile for the Stanford-Binet IQ test is 115. (Recall that the mean is 100 and the standard deviation is 15.) Verify that this is true by computing the standardized score

Answer 1

Find the z value for 0.84 probability, that is the 84th percentile: 0.994

z = (x - mean)/SD, where x is 84th percentile score 115, mean = 100 and SD = 15

compute (x - mean)/SD = (115-100)/15 = 1 (that matches within round off).