Apple Numbers '08 - Manual (Page 276)

276 Chapter 12 Dictionary of Functions
If the values you are analyzing are only a sample of a larger population, you might
want to use the STDEV function instead.
Cells that don’t contain numbers are ignored. If you want to include text or Boolean
values in the computation, use the STDEVPA function.
STDEVPA
The STDEVPA function calculates the standard deviation of a set of values, including
text and Boolean values, based on the population (true) variance.
STDEVPA(value, [value, . . .])
 value: One or more numeric or Boolean values or references to cells containing
numeric, textual, or Boolean values.
Notes
Unlike the STDEVP function, which ignores cells that don’t contain numbers, STDEVPA
assigns a value of 0 to any text value, 0 to the Boolean value FALSE, and 1 to the
Boolean value TRUE and includes them in the computation.
Entering text directly results in an error. Referencing a cell containing text is evaluated
as 0. Boolean values can be entered directly or as cell references.
If the values you are analyzing are only a sample of a larger population, you might
want to use the STDEVA function instead.
Examples
STDEVP(5, 5, 5, 5, 6) returns a standard deviation of 0.4 based on an average of 5.2.
STDEVP(1, 2, 3, 4, 5) returns a standard deviation of 1.41 based on an average of 3.
STDEVP(1, 1, 1, 1, 6) returns a standard deviation of 2 based on an average of 2.
STDEVP(2, 2, 4, 6, 6) returns a standard deviation of 1.79 based on an average of 4. Compare with
STDEV(2, 2, 4, 6, 6), which uses the sample (unbiased) variance to return a standard deviation of 2.
Examples
STDEVPA(TRUE, TRUE, TRUE, TRUE, 6) returns 2. Each TRUE value is counted as a 1.
STDEVPA("a", 3, 6, 3, "b") displays an error.