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This operation calculates the biased standard deviation of the values found in a specified column for each grouping occurrence. If you want to exclude null values, you can use the Non-null standard deviation (biased) (nnstddev) operation and if you want to calculate the unbiased variant, you can use the Standard deviation (unbiased) (ustddev) operation.
How does it work in the search window?
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Before being able to perform this operation, you have to group your data. Be aware that the columns used as arguments for the grouping operation will not be available to select as arguments for the aggregation operation. |
After grouping the data, select Aggregation in the search window toolbar, then select the Standard deviation (biased) operation. You need to specify one argument:
Argument | Data type |
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Biased standard deviation of mandatory | integer, float |
The data type of the aggregated values is integer or float.
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In the siem.logtrust.web.activity table, we want to calculate the biased standard deviation of the values in the responseLength column during each 5-minute period. Before aggregating the data, the table must be grouped in 5-minute intervals. Then we will perform the aggregation using the Standard deviation (biased) operation.
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Biased standard deviation of → responseLength column
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Click Aggregate function and you will see the following result:
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