#### Answer

The z scores are -2 and 2, the IQ scores are $31.6 \ cm$ and 41.6 cm$.

#### Work Step by Step

If a value is unusual, then it is more than two standard deviations far from the mean. $Minimum \ usual \ value=mean-2\cdot(standard \ deviation)=36.6 \ cm-2\cdot2.5 \ cm=31.6 \ cm$
$Maximum \ usual \ value=mean+2\cdot(standard \ deviation)=36.6 \ cm+2\cdot2.5 \ cm=41.6 \ cm$. Therefore the z scores are -2 and 2, the IQ scores are $31.6 \ cm$ and 41.6 \ cm$.