A simple example of data entry

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A small 2-day experiment has been undertaken from which the population size will be estimated using a Petersen-Lincoln index.

On day 1, 56 individuals were caught and marked.

On day 2, 120 animals were caught, of which 25 bore marks from day 1.


Choose File: New to create a new data file.




Next you will be asked to choose the type of data you wish to input. Click on the Closed Type Summary button.


New data type


You will be asked to enter the number of samples; type in 2.



input 2


You will now be presented with an empty grid into which to type the observations. When completed the data grid should look like this:


simple example data


U(2) = 95 because the new captures = 120-25


f(1) = 56+120-25=151


To undertake the calculations select Closed methods: Temporal change in capture probability (Schnabel ML, Mt) and the results will be displayed in the Mt tab. This will be the maximum likelihood estimate of population size, as per the Petersen-Lincoln index.


result simple example