Answer
The relative error in calculating $I$ is the same in magnitude as the relative error in $R$.
Work Step by Step
$V = R~I$
$I = \frac{V}{R}$
$dI = -\frac{V}{R^2}~dR$
We can find an expression for the relative error in calculating $I$:
$\frac{dI}{I} = \frac{-\frac{V}{R^2}~dR}{V/R}$
$\frac{dI}{I} = -\frac{dR}{R}$
Therefore, the relative error in calculating $I$ is the same in magnitude as the relative error in $R$.