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FERITSCOPE® DMP30 Description
3.8 Statistical characteristic variables
– Mean Value
Arithmetic mean value ( ) of all measured readings. The arithmetic mean value is
the summation of all measured readings xi of a batch or block, divided by the num-
ber of measured readings (n).
n – Number
Number of all measured readings in a batch or per block.
s – Std. Dev.
Standard deviation is a measure for the variation of individual measured readings (of
a batch or block) around their common mean value ( ). It equals the mean square
deviation of the measured readings from the mean value.
R – Range
The range equals the difference between the highest and lowest measured reading
in a batch or block.
V[%] – Coeff. of Variation
Coefficient of variation, percentage variation of a series of measurements, i.e. stan-
dard deviation (s) relative to the mean value ( ). The coefficient of variation is a char-
acteristic process constant. A sudden change in the coefficient of variation indicates
a change in process conditions.
Min – Low. Value
Lowest measured reading in a batch or block.
Max – High. Value
Highest measured reading in a batch or block.
<LSL – n < LSL
Number of measured readings below the lower specification limit (LSL).
>USL – n > USL
Number of measured readings above the upper specification limit (USL).
No. – Block No. (No.)
Number of the current/selected measured reading block.
x
x
x
x
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