FISCHER FISCHERSCOPE X-RAY XDLM 231, Operator'S Manual

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196 FISCHERSCOPE ® X-RAY
Addendum
23.1.3 Final Result – Variable Block Definition
Manual block creation (Block definition variable) is enabled for the product.
Parameter Description Equation
Mean value Arithmetic mean value of the single
readings
: Single readings of the selected
blocks
: Number of measurements of the
selected blocks
Confidence
interval
q
Each measurement device produces
random measurement errors. With a
certain probability (confidence
level), the true value of the
measured parameter lies in an
interval (double-sided confidence
interval) around the measured mean
value
of a measurement series
(block/group). The borders of this
interval are at a distance
q
from the
true value .
q
is calculated according to the
equation below assuming a normal
distribution for a confidence level of
95 %:
t : Quantile of the Student’s t-distri-
bution (Student’s factor), can be
obtained from tables in
common publications [1]
s : Standard deviation
n : Number of measurements of the
selected blocks
Standard
deviation
s
The standard deviation is a measure
of the dispersion of the single
readings of a measurement series
about the mean value.
: Mean value of the single read-
ings of the selected blocks
: Single readings of the selected
blocks
n
: Number of measurements
Coefficient of
variation
V
[%]
Standard deviation relating to the
mean value
s
: Standard deviation
: Mean value of the single read-
ings of the selected blocks
x
x
1
n
--- x
i
i 1 =
n

=
x
i
n

x

x q –

x q +
 
q t
f 1 0 025

– ;
s
n
------- =
s
1
n 1 –
------------ x x
i
–
 
2
i 1 =
n

=
x
x
i
V
s
x
-- 100 =
x