3
Basic operation of the DS252
42
17 : Standard Deviation
Select a calculating formula the standard deviation.
There are two types of calculating formula.
Details of setting
σ
n
................ All the data in a group is used to obtain the standard deviation of the group.
σ
n-1
............. Several pieces of sample data out of a group are used to estimate the standard
deviation of the whole group.
Caution for selection
By
σ
n-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.
Setting name
17 : Standard Deviation (STD MODE)
Selectable items
00 :
σ
n
(initial value)
01 :
σ
n-1
Display
1 7 : S T D M O D E
0 0 : σ n
σ
n
○
○
○
○
○
○
○
○
○
Group
All the data in the group is recorded to obtain
the standard deviation.
σ
n
χ
i
χ
–
(
)
2
i
1
=
n
∑
n
------------------------
=
σ
n-1
○
○
○
○
○
○
○
○
○
Group
Only several pieces of sample data are recorded
to estimate the standard deviation of the whole.
σ
n
1
–
χ
i
χ
–
(
)
2
i
1
=
n
∑
n
1
–
------------------------
=
Summary of Contents for DS252
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