Question: Comparing IQ scores. The Wechsler Adult Intelligence Scale (WAIS) is an IQ test. Scores on the WAIS for the 20 to 34 age group are approximately Normally distributed with mean 110 and standard deviation 15. Scores for the 60 to 64 age group are approximately Normally distributed with mean 90 and standard deviation 15. Sarah, who is 30, scores 130 on the WAIS. Her mother, who is 60, takes the test and scores 115.

(a) Express both scores as standard scores that show where each woman stands within her own age group.

(b) Who scored higher relative to her age group, Sarah or her mother? Who has the higher absolute level of the variable measured by the test?