Spc Report Variables; Regression Chart Variables - Micromeritics ASAP 2460 Operator's Manual

ASAP 2460 Operator's Manual

SPC Report Variables

Regression 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.
 x
i
---------
X =
N
 y
i
---------
Y =
N
 x 
------------------------------------------ -
Slope =
The coefficient of Correlation for this line is also calculated in the usual way. (Refer to Mathematical
Handbook for Scientists and Engineers, by Granino A. Korn and Theresa M. Korn, Copyright 1961,
1968 McGraw Hill, Sec. 18.4.)
 x 

= --------------------------
x
 y 

= ------------------------- -
y
Cov x y   
Correlation Coefficient =
246-42800-01 - Aug 2013
 y  
– X – Y
i i
2
 x  
– X
i
2

– X
i
N
2

– Y
i
N
 x   y  
– X – Y
i i
------------------------------------------ -
=
N
Cov x y   
-----------------------
 
x y
Appendix C
C-45