Filemaker Pro 8.5 Educational Maintenance T3 TJ083LL/A User Manual
Product codes
TJ083LL/A
Chapter 2
|
Aggregate functions 29
Description
Returns the variance of a population represented by a series of non-blank values. The
variance of a population distribution is a measure of how spread out the distribution is.
Use this function on any of the following fields:
•
variance of a population distribution is a measure of how spread out the distribution is.
Use this function on any of the following fields:
•
a repeating field (repeatingField).
•
a field in matching
specified by (table::field), whether or not
these records appear in a portal.
•
several non-repeating fields in a
(field1;field2;field3...).
•
corresponding repetitions of repeating fields in a record
(repeatingField1;repeatingField2;repeatingField3), if the result is
(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
(table::field1;table::field2;...). You can include fields from different
(table 1::field A;table 2::field B...).
Examples
displays the related values 5, 6, 7, and 8 in Scores.
VarianceP(table::Scores) returns
1.25
.
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.
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 population variance for each
class is:
Class 1:
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 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.
2 because the scores for Class 1 are more tightly clustered.
VarianceP
x
1
2
x
2
2
… x
n
2
+
+
+
n
------------------------------------------
x
1
x
2
… x
n
+
+
+
n
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