LumaSense Technologies 3434i SF6 Leak Detector - Manual (Page 97)

Chapter 8
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BE6028-14 3434i SF6 Leak Detector LumaSense Technologies A/S
Page 97 of 191
8.2.1 Statistical Analysis Terms
In the statistical analysis of the measurement results for each gas
(see 3 in Fig.8.1 ) the following statistics appear:
The Mean Value (µ) – this is the linear average of all
measurements of a gas taken during the total monitoring period.
The calculation of “the mean value” can be expressed
mathematically as follows:
The Mean Value =
( )
N
C
N n
n
n
å
=
= = 1 m
Where: N = measurement cycles performed during the
monitoring period (T) between the cursors.
c
n
= gas concentrations (where n = 1 to N)
The Standard Deviation (σ) – this is the standard deviation of a
particular gas’s measurements from the mean value (µ) of this
gas. Standard deviation can be expressed mathematically as
follows:
The Standard Deviation =
( )
1
1
2
-
-
=
å
=
=
N
Cn
N n
n
m
s
Where: µ = the mean value
C
n
= individual gas concentrations
N = total number of measurements
8.2.2 Symbols used in Displayed Measurement Data
If an asterisk (*) appears on the display alongside any gas
concentration, it indicates that something happened during the
measurement. You can find out what the asterisk indicates by
pressing the INFO button. The following display appears for a short
period of time:
GAS X: COMMON MARK: PEOW GAS MARK: BFA
EVENT NO: xxxx TIME: hh:mm