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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 "SubAverage" Abacus: Also create an Abacus to calculate the square of the difference between the sample value and the SubAverage (Mean Diff. Sq.): In the "Sample Set" Relation, create: 1. An Abacus to find the SubCount (n) of the sample records: 2. An Abacus to find the SubTotal 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. 