E$.$g$.$: $$5000$ bond, $4\%$ coupon rate, $1$ year, bought for:

$$4700$: Rate of return $=\frac{(\text{\$}200+\text{\$}300)}{4700}100=10\mathrm{.}64\%$

$$4900$: Rate of return $=\frac{(\text{\$}200+\text{\$}100)}{4900}100=6\mathrm{.}12\%$

$$$100$: Rate of return $=\frac{(\text{\$}200-\text{\$}100)}{5100}100=1\mathrm{.}96\%$

The higher the purchase price, the lower the yield

The lower the purchase price, the higher the yield