Spc Report Variables; Regressions Chart Variables - Micromeritics ASAP 2020 Confirm Operator's Manual

Appendix C

SPC Report Variables

Regressions Chart Variables

The line of best fit for the Regression Chart is calculated by the usual Least Squares method.
(Refer to BASIC Scientific Subroutines Vol II, by F.R. Ruckdeschel, Copyright 1981 BYTE
Publications/McGraw Hill, p. 16.) If there is only a single point or all N points have the same
x-value, there can be no line of best fit in the standard form.
XAve
XAve
Slope
The coefficient of Correlation for this line is also calculated in the usual way. (Refer to Math-
ematical Handbook for Scientists and Engineers, by Granino A. Korn and Theresa M. Korn,
Copyright 1961, 1968 McGraw Hill, Sec. 18.4.)

x

y
Cov x y 
Correlation Coefficient
202-42811-01 - Mar 2011
 x
i
-------- -
=
N
 y
i
-------- -
=
N
 x   y 
– XAve
i i
-------------------------------------------------------------- -
=
 x 
– XAve
i
2
 x  
– XAve
i
= ----------------------------------- -
N
2
 y  
– XAve
i
= ----------------------------------- -
N
 x 
– XAve
  i
-------------------------------------------------------------- -
=
N

– XAve
2

 y  
– XAve
i
Cov x y   
-----------------------
=
 
x y
ASAP 2020 Confirm
C-45