Answer
$y$ does not vary directly with $x$.
Work Step by Step
To find the rule, we plug the $x$ values and $y$ values into the ratio $\frac{y}{x} = k$ to see if each set of $x$ and $y$ have the same constant of variation ($k$). If they do, then $y$ varies directly with $x$:
$\dfrac{1}{4}\ne\dfrac{2}{6}\ne\dfrac{3}{8}$
In this exercise, $\frac{y}{x}$ is not constant, so $y$ does not vary directly with $x$.