  Fast Radio Bursts (FRBs) are intense radio flashes from the sky that are
characterized by millisecond durations and Jansky-level flux densities. We
carried out a statistical analysis on FRBs discovered. Their mean dispersion
measure, after subtracting the contribution from the interstellar medium of our
Galaxy, is found to be $\sim 660\,\rm pc\,cm^{-3}$, supporting their being from
cosmological origin. Their energy released in radio band spans about two orders
of magnitude, with a mean value of $\sim 10^{39}$ ergs. More interestingly,
although the FRB study is still in a very early phase, the published collection
of FRBs enables us to derive a useful intensity distribution function. For the
16 non-repeating FRBs detected by Parkes telescope and the Green Bank
Telescope, the intensity distribution can be described as $dN/dF_{\rm obs} =
(4.1 \pm 1.3) \times 10^3 \, F_{\rm obs}^{-1.1\pm0.2} \; \rm
sky^{-1}\,day^{-1}$, where $F_{\rm obs}$ is the observed radio fluence in units
of Jy~ms. Here the power-law index is significantly flatter than the expected
value of 2.5 for standard candles distributed homogeneously in a flat Euclidean
space. Based on this intensity distribution function, the Five-hundred-meter
Aperture Spherical radio Telescope (FAST) will be able to detect about 5 FRBs
for every 1000 hours of observation time.
