## 3. Statistical propertiesThe simplest description of the statistical properties of the mass-transfer history is the differential probability of having a particular mass-transfer rate . For convenience, we will use the relative mass-transfer rate , where (Fig. 3) and is the relative "spottedness" (i.e. 0 if no spots are present and 1 if spots block the mass-transfer completely). is derivable from the cumulative probability distribution function , defined as can be trivially derived from the observed values of by noting that it is simply one minus the rank of the sorted values divided by the number of measurements minus one. The observed and
curves for AM Her are shown in
Fig. 4. Note that the median value of
()
is 0.75,
© European Southern Observatory (ESO) 2000 Online publication: October 10, 2000 |