Calculations - Siemens ARCADIS Avantic Maintenance Instruction

5 - 2

2.2 Calculations

Variation coefficient C
For n individual measurements, the coefficient of variation C amounts to:
s = calculated standard deviation
= mean value of all individual measurements
x
x = measured value of the ith measurements.
i
1.
2.
Measurement
Measurement
3.
4.
5.
6.
Coefficient of variation C =
ARCADIS Avantic
n
s
1
Σ
C = =
x
x
i = 1
To obtain the average x, the 4 dose values are added and the sum is divided by 4.
To obtain the difference, the average value is subtracted from each individual
measured value and entered into the column provided
Radiation Exposure (x
1
2
3
4
* Disregard the sign if negative numbers are obtained.
Square the differences
Square of the difference (x
1
2
3
4
Σ
Add the 4results: ....................:
Divide the sum by 4: ...............
Obtain the square root of the new result: Square root S: ..................
Divide the square root S by the average value x determined in step 1:
1/2
2
(x - x)
i
n -1
) Average ( )
i
-
x
i
S
x
C = . . . . . . . . . . . . . . .
SPR2-330.662.01
Rev. 02 05.06
Function tests
= Difference*
x
2
)
(must be
Page 2 of 6
CS PS SP
5
≤
0.05)
Siemens AG
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