Answer
student
Work Step by Step
$\text{z-score}=\frac{\text{data item-mean}}{\text{standard deviation}}$.
Hence $z_1=\frac{120-100}{10}=2, z_2=\frac{128-100}{15}=1.87$.
$z_1\gt z_2$, thus the first person has a higher IQ.
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