Apple iWork '09 - Manual (Page 303)

Chapter 10 Statistical Functions 303
“STDEVP” on page 293
“STDEVPA” on page 294
“VAR” on page 298
“VARA” on page 300
“VARPA” on page 303
“Survey Results Example” on page 362
“Listing of Statistical Functions” on page 225
“Value Types” on page 36
“The Elements of Formulas” on page 15
“Using the Keyboard and Mouse to Create and Edit Formulas” on page 26
“Pasting from Examples in Help” on page 41
VARPA
The VARPA function returns the sample (unbiased) variance, a measure of dispersion, of
a collection of values, including text and Boolean values.
VARPA(value, value…)
 value: A value. value can contain any value type.
 value…: Optionally include one or more additional values. All numeric values must
be of the same type. You cannot mix numbers, dates, and duration values.
Usage Notes
The VARPA function finds the population, or true, variance (as opposed to the Â
sample, or unbiased, variance) by dividing the sum of the squares of the deviations
of the data points.
It is appropriate to use VARPA when the specified values represent the entire
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collection or population. If the values you are analyzing represent only a sample of a
larger population, use the VARA function.
VARPA assigns a value of 0 to any text value, 0 to the Boolean value FALSE, and 1
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to the Boolean value TRUE and includes them in the computation. Empty cells are
ignored. If you do not want to include text or Boolean values in the computation,
use the VAR function.
The square root of the variance returned by the VARPA function is returned by the
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STDEVPA function.