If the dead time is not known, a statistical analysis can yield the correct count. For example, (Meeks 2008), if t i are a set of intervals between measurements, then the t i will have a shifted exponential distribution, but if a fixed value D is subtracted from each interval, with negative values discarded, the distribution will be exponential as long as D is greater than the dead time τ τ . For an exponential distribution, the following relationship holds: