Stdev, 290 stdev – Apple iWork '09 User Manual
Page 290
STDEV
The STDEV function returns the standard deviation, a measure of dispersion, of a
collection of values based on their sample (unbiased) variance.
STDEV(num-date-dur, num-date-dur…)
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num-date-dur: A value. num-date-dur is a number value, a date/time value, or a
duration value.
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num-date-dur…: One or more additional values (a minimum of two values are
required). All num-date-dur values must be of the same type.
Usage Notes
It is appropriate to use STDEV when the specified values represent only a sample of
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a larger population. If the values you are analyzing represent the entire collection or
population, use the STDEVP function.
If you want to include text or Boolean values in the computation, use the STDEVA
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function.
The standard deviation is the square root of the variance returned by the VAR
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function.
Example
Assume you have administered five tests to a group of students. You have arbitrarily selected
five students to represent the total population of students (note that this is an example only; this
would not likely be statistically valid). Using the sample data, you could use the STDEV function to
determine which test had the widest dispersion of test scores.
The results of the STDEV functions are approximately 22.8035, 24.5357, 9.5026, 8.0747, and 3.3466. So
test 2 had the highest dispersion, followed closely by test 1. The other three tests had low dispersion.
Test 1
Test 2
Test 3
Test 4
Test 5
Student 1
75
82
90
78
84
Student 2
100
90
95
88
90
Student 3
40
80
78
90
85
Student 4
80
35
95
98
92
Student 5
90
98
75
97
88
=STDEV(B2:B6)
=STDEV(C2:C6)
=STDEV(D2:D6)
=STDEV(E2:E6)
=STDEV(F2:F6)
Related Topics
For related functions and additional information, see:
290
Chapter 10
Statistical Functions