Question

why do you have to repeat a sample when you capture no marked beads the second time

Answer 1

The Mark-Recapture technique is used to estimate the size of a population where it is no t possible count every individual. In this method we capture small number of individuala and mark them, and release back into the population. Later we catch another small group, and record how many have a mark. In a small population, we are more likely to recapture marked individuals, whereas in a large population, it is less likely. This can be expressed mathematically using the equation below.

N = (M*C) / R

N = estimated Number of individuals in the population

M = number of individuals captured and marked

C = total number captured the second time (with and without a mark)

R= number of individuals recaptured (those with a mark)

If no marked individuals are recaptured, R = 0 and and result is undefined. So we have to mark more individuals and try again.