Improved time-interval analysis

Several extensions of the halflife analysis method recently suggested by Horvat and Hardy are put forward. Goodness-of-fit testing is included, and the method is extended to cases where more information is available for each decay event which allows applications also for e.g. $\gamma$ decay data. The results are tested with Monte Carlo simulations and are applied to the decays of ${}^{64}$Cu and ${}^{56}$Mn.