A person scores 81 on a test of verbal ability and 6.4 on a 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? Explain your answer to a person who has never had a course in statistics.
statistics - Marth, Tuesday, June 30, 2009 at 10:20am
Start by finding the z scores.
z = (value - mean)/SD
verbal: z = (81-50)/20
z = 1.55
quantitative: z = (6.4-0)/5
z = 1.28
Compare the z scores. 1.55 > 1.28. Therefore, the person's score exceeded the mean by more in the verbal test.