Addendum To Counting By Weighing And The Seed Testing Problem

The subject of counting by weighing as addressed in Ridout & Suntheralingam (1997) is revisited. When the coefficient of variation of the seed weights is known, we show how to modify the seed testing procedure in the aforementioned paper to account for the uncertainty introduced by obtaining a given number of seeds by weight, rather than exact counting. We find that counting by weighing requires a greater number of seeds per sub-sample than that required by the exact counting method of Ridout & Roberts (1997). Furthermore, the number of seeds per sub-sample increases with decreasing initial sample size used to estimate mean seed weight