Extracts a random sample
without replacement (to prevent repetition) from N
different items (the "lot"), with values
i = 1..N, considering
that the lot is constituted of m subgroups, each of size
Sk, k = 1..m, and, of course,
∑k Sk = N.
Here, these sizes are calculated at random (to spare the user
giving them).
An analogy to make the concept clearer is a certain deck
of cards with, for example: N = 35 cards and m = 6 suits,
with sizes S = (8, 13, 0, 5, 9),
which add up to the desired total,
N.
In the application in this Plate, only the sample size,
n, is prescribed. A further constraint might be extracting at least
one item (or a fraction) from each subgroup.
The procedure is a generalization of the classical
extraction of a sample without replacement. |
