Everything Else
Variance and Standard Deviation
Creating the Equivalent

Variance and Standard Deviation are two statistical calculations that are frequently used to analyze data. The formulae below derive Variance and Standard Deviation:

To find the Standard Deviation of a set of records, use the following technique. In this example, there are two Relations: one Relation with one record per sample set, and another Relation to store the samples. In the Relation which contains the sample records, create a "Sub-Average" Abacus:

Also create an Abacus to calculate the square of the difference between the sample value and the Sub-Average (Mean Diff. Sq.):

In the "Sample Set" Relation, create:

1. An Abacus to find the Sub-Count (n) of the sample records:

2. An Abacus to find the Sub-Total of the Mean Diff. Sq. Abacus:

3. An Abacus to calculate the Variance:

4. An Abacus to calculate the Standard Deviation:

Place the "Variance" and "Standard Deviation" Abacii on the forms in the "Sample Set" Relation where you wish to view this information.