In Young's double-slit experiment, the intensities at two points ${\mathrm{P}}_1$ and ${\mathrm{P}}_2$ on the screen are ${\mathrm{I}}_1$ and ${\mathrm{I}}_2$, respectively. If ${\mathrm{P}}_1$ is located at the central bright fringe and ${\mathrm{P}}_2$ is located at a distance equal to a quarter of fringe width from ${\mathrm{P}}_1$, then $\frac{{\mathrm{I}}_1}{{\mathrm{I}}_2}$ is