Standard Deviation - Unipulse DS252 Operation Manual

3 Basic operation of the DS252

17 : Standard Deviation

Select a calculating formula the standard deviation.
There are two types of calculating formula.
Setting name
Selectable items 00 : σ
Display
Details of setting
σ
................ All the data in a group is used to obtain the standard deviation of the group.
n
σ
............. Several pieces of sample data out of a group are used to estimate the standard
n-1
σ n 1
Caution for selection
By σn-1, part of the entire recorded data is extracted as samples and the standard deviation is
calculated from the data of those samples alone. Therefore, if it is used when the amount of data is
small, the reliability of the value will become low.
42
17 : Standard Deviation (STD MODE)
(initial value)
n
01 : σ
n-1
1 7 : S T D M O D E
0 0 : σ n
n
( χ i χ
∑
–
i = 1
σ n
=
- - - - - - - - - - - - - - - - - - - - - - - -
n
deviation of the whole group.
n
( χ i χ
∑
–
i = 1
=
- - - - - - - - - - - - - - - - - - - - - - - -
–
n 1
–
σ
n
○
○
2
○
)
All the data in the group is recorded to obtain
the standard deviation.
σ
n-1
○
○
2
)
○
Only several pieces of sample data are recorded
to estimate the standard deviation of the whole.
Group
○
○ ○
○
○
○
Group
○
○ ○
○
○
○