Standard score (z-score) interpretation.
A person score 81 on a test of verbal ability and 6.4 on the test of quantitative ability. For the verbal ability test, the mean for people in general is 50 and the standard deviation is 20. For the quantitative ability test, the mean for people in general is 0 and the standard deviation is 5. Which is this person's stronger ability: Verbal or quantitative? Give details your answer to a person who has never had a course in statistics.