### Variance (fld), Variance (fld, condFld), Variance (fld, condFld, cond), Variance (x)

Basic and Crystal syntax.

##### Arguments

- fld is any valid database or formula field that can be evaluated by the function.
- condFld is a field used to group the values in fld by.
- cond is a String indicating the type of grouping for condFld. You only specify this argument when condFld is a Date, Time, DateTime or Boolean field. For more information on the valid strings for this argument, see Conditions for summary functions.
- x is an array of values that can be evaluated by the function being used.

##### Returns

Fractional Number

##### Action

Enables you to find the variance of a set of values in your report. For example:

- You can calculate the grand total variance for all values in a field. For information about this kind of summary, see SummaryFunction (fld).
- You can calculate the variance for all values within a group (for example, sales grouped by the state that they come from). For information on this kind of summary, see SummaryFunction (fld, condFld).
- You can calculate the variance for all values within a group in which grouping is controlled by changes in a date or Boolean field (for example, sales grouped by the month in which they were made). For information on this kind of summary, see SummaryFunction (fld, condFld, cond).
- If you specify a set of individual values, you can compute the variance of the values in the set. For information on this kind of summary, see Array summary functions (x).

##### Examples

The following examples are applicable to both Basic and Crystal syntax:

`Variance({file.AMOUNT})`

Calculates the variance of all values in the Amount field.

`Variance({file.RESULTS}, {file.DATE},"daily")`

Calculates the variation for each group of laboratory test results in the Results field. The test results are separated into groups whenever the value in the Date field changes to a new day.

The following examples are applicable to Crystal syntax:

`Variance({file.SCORES}, {file.TEACHERS}) % Variance({file.TEACHERS})`

Groups values in the Scores field by teacher, and calculates the variance for each teacher group as a percentage of the variance of the values for the entire report (for all teachers listed).

`Variance([{file.QTY1}, {file.QTY2}, {file.QTY3}, {file.QTY4}])`

Returns 17.00 where Qty1 = 2, Qty2 = 2, Qty3 = 10, and Qty4 = 8.

##### Comments

Variance is calculated using the following technique:

- It calculates the average (mean) value for the items in the sample.
- It subtracts the average value from the value of each item.
- It squares the difference for each item.
- It adds the squared differences for all of the items in the sample.
- It divides the sum by one less than the number of items in the sample (N - 1). The result is the variance. Compare this final step to the PopulationVariance (fld), PopulationVariance (fld, condFld), PopulationVariance (fld, condFld, cond), PopulationVariance (x).

Note: Using this function in a formula forces the formula to be evaluated at print time.

For more information on evaluation time considerations, see Evaluation Time functions.

Seagate Software, Inc. http://www.seagatesoftware.com Please send comments to: techpubs@seagatesoftware.com