Deriving median disk lifetimes from disk lifetime distributions

Observations show that individual protoplanetary disk lifetimes vary from \mbox{$<$ 1 Myr} to $\gg$ 20 Myr. The disk lifetime distribution is currently unknown. For the example of a Gaussian distribution of the disk lifetime, I suggest a simple method for deducing such a disk lifetimes distribution. The median disk lifetimes inferred with this method is also shown.