Checkline FH Series - Manual (Page 60)

© ElektroPhysik MiniTest 7200 FH / MiniTest 7400 FH 60
15.3 Statistical Terms
The statistical evaluation will help you to assess the quality of your product.
Average (Mean)
The sum of single readings divided by the total number of readings.
x
x
n
=
∑
Standard Deviation (STD. DEV.) s (s =
σ
= sigma)
The sample standard deviation is a statistic that measures how “dispersed“ the sample is around
the sample mean. The sample standard deviation increases with increasing spread out. The
standard deviation of a set of numbers is the root mean square of the variance s².
s
x x
n
2
2
1
=
−
−
∑ ( )
s s
= 2
Variance
The variance of a list is the square of the standard deviation of the list, that is, the average of the
squares of the deviations of the numbers in the list from their mean divided by the (number of
readings minus 1).
Variation coefficient (Var.-coeff.)
The variation coefficient is the standard deviation divided by the arithmetic mean. The variation
coefficient is indicated in percent.
K
s
x
var %
= Ч
100