Micromeritics Gemini VII 2390a, Operator'S Manual

Page: 333 / 426

Gemini VII Appendix C
239-42828-01 - Dec 2012 C-39
SPC Report Variables
Regression Chart Variables
XAve

x
i
N
---------
=
YAve

y
i
N
---------
=
Slope

x
i
XAve
–
 
y
i
YAve
–
 

x
i
XAve
–
 
2
---------------------------------------------------------------
=

x

x
i
XAve
–
 
2
N
------------------------------------- =

y

y
i
YAve
–
 
2
N
------------------------------------ =
Cov x y
  

x
i
XAve
–
 
y
i
YAve
–
 
N
---------------------------------------------------------------
=
Correlation Coefficient
Cov x y
  

x

y
-----------------------
=
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.
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.)