Description
Enables you to find the variance of a set of values in your report.
Overloads
Variance (fld, condFld, cond)
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 Number or Currency values that can be evaluated by the function being used.
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.
You can calculate the variance for all values within a group (for example, sales grouped by the state that they come from).
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).
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.
Examples
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.
Variance({file.SCORES}, {file.TEACHERS}) % Variance({file.SCORES})
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.
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.