BlueLab - BioAmostra

Download the BioAmostra to your device.

Select the BioAmostra on your device by clicking on the icon similar to

Menu -> Define Class Lengths

Enter the range of values ​​for the length class. If you have already defined them, they are shown as in the figure on the side, from 170 to 390 in intervals of 10.

To define a new range of length classes choose the minimum, maximum value and the interval, then click on "Build Class Lengths"

Note that each time you create a new length class it will delete any individuals you have entered in the meantime.

Menu -> Individuals per Class

Click on the class length and enter the number of individuals in that class.

Complete the number of individuals for all classes. The number of individuals can be 0.

Menu -> Biologic

Define the parameters that may be used:

In the example of the figure to the side, it is indicated above that there are 1334 individuals distributed in 23 compliance classes, two of which have no individuals, and the pair (min, max) that indicates the minimum and maximum number of individuals among all classes with individuals was 3 and 161 respectively

Minimum number of individuals per length class (20 in this example). This value only makes sense if this number is less than min.

The program determines a set of optimal pairs (max, total) that allow to select a certain sample with an integer number of individuals in each class of length. To limit the list of these combinations, it is possible to choose the range of values ​​for max (Maximum number of samples per Class interval) and total (Total number of individuals). To show the desired list, it is necessary to choose between ALL and USE LIMITS in the selector.

When selecting the optimal pair (in this example 123, 1031) it becomes available as seen in the figure on the side, where it is possible to edit and use another value.

The calculation is done in a Proportional way using the maximum number per class of length (Maximum number of samples per Class interval), in this case 123, or Total number of individuals, in this example 1031

Menu -> Biologic -> Proportional

Choosing as a criterion the maximum number of 123 individuals for each length class, the calculation made shows the following:

The spectral power of the original normalized distribution (minimum = 0.0 and maximum = 1.0) is 8.0 anonymized unit (a.i.). The spectral power of the new distribution is 8.01 (u.a). The difference in power is -0.0001% which indicates a similarity of both spectra; distributions.

The cumulative error is 5.56 individuals and the cumulative quadratic error - and 0.0002205 also indicating a correspondence between the two distributions.

The graph shows the original distribution in green and the chosen sample distribution in red.

The sample chosen is 1031 individuals, which represents 77.29% of the total number of individuals in the original sample.

The figures below show the length classes with the number of individuals in the calculated sample.

Eg: (51) Class 190 -> 39

It indicates that the length class of 190 (mm) has 51 individuals in the original sample and, according to the chosen criterion, it is enough to sample 39 individuals.

Note that the criterion of the maximum number of individuals being 123 is realized in the class with the largest number of individuals (161) Class 230 -> 123

Menu -> Biologic -> Proportional

Choosing as a criterion the total number of individuals 1000, a value that does not fit the optimal values, we have after the calculation made the following result according to the images below:

The spectral power of the original normalized distribution remains at 8.0 (a.i.). The spectral power of the new normalized distribution is 7.97 (u.a), which leads to a power difference of + 0.003% which also indicates a similarity of both distributions.

The accumulated error is 6.1 individuals and the accumulated quadratic error is 0.0002604 also indicating a correspondence between the two distributions.

The graph shows in green the original distribution and in red the distribution of the chosen sample.

The sample chosen is 1002 individuals (the closest value to 1000 orders, in excess) which represents 75.11% of the total number of individuals in the original sample.

The figures below show the length classes with the number of individuals in the calculated sample.

Note that in both criteria (maximum number of samples per class or total number of samples), the criterion that the minimum number of samples per class is 20 as defined above cannot be met since there are classes that have a number total number of individuals below 20 in the original distribution.