Variance
Purpose
Returns the variance of a sample represented by a series of non-blank values in a field.
Format
Variance(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
FileMaker Pro 7.0
Description
The variance of a 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...).
Examples
A portal displays the related values 5, 6, 7, and 8 in Scores.
Variance(table::Scores) returns 1.66666666....
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.
Variance(Field4) results in an error since the variance of a single value is not defined.
Variance(Field1;Field2;Field3) returns 7, 9.33333333..., 4.5, 8 if the calculation is a repeating field.
Student example
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 variance for each class is:
Class 1: 3.80952380...
Class 2: 361.90476190...
The variance for Class 1 is much lower than the variance for Class 2, because the scores for Class 2 are more spread out.
Related topics
