VarianceP
Returns the variance of a population represented by a series of non-blank values in a field.
Format
VarianceP ( field {; field...} )
Parameters
field - any related field, repeating field, or set of non-repeating fields; or an expression that returns a field, repeating field, or set of non-repeating fields.
Parameters in braces { } are optional.
Data type returned
number
Originated in version
7.0
Description
The variance of a population distribution is a measure of how spread out the distribution is. Field can be any of the following:
- a repeating field
(repeatingField). - a field in matching related records specified by
(table::field), whether or not these records appear in a portal. - several non-repeating fields in a record
(field1;field2;field3...). - corresponding repetitions of repeating fields in a record
(repeatingField1;repeatingField2;repeatingField3), if the result is returned in a repeating field with at least the same number of repeats. - several fields in the first matching record specified by
(table::field1;table::field2;...). You can include fields from different tables(table 1::field A;table 2::field B...).
Example 1
A portal displays the related values 5, 6, 7, and 8 in Scores.
VarianceP(table::Scores) returns 1.25.
Example 2
In the following examples:
- Field1 contains two repetitions with values of 1 and 2.
- Field2 contains four repetitions with values of 5, 6, 7, and 8.
- Field3 contains four repetitions with values of 6, 0, 4, and 4.
- Field4 contains one repetition with a value of 3.
VarianceP(Field4) results in an error since the variance of a single value is not defined.
VarianceP(Field1;Field2;Field3) returns 4.66666666..., 6.22222222..., 2.25, 4 if the calculation is a repeating field.
Example 3
Two classes of students take an exam. Class 1 has scores of 70, 71, 70, 74, 75, 73, 72 and Class 2 has scores of 55, 80, 75, 40, 65, 50, 95. The population variance for each class is:
Class 1: 3.26530612...
Class 2: 310.20408163...
The population variance for Class 1 is much lower than the population variance for Class 2 because the scores for Class 1 are more tightly clustered.