Micromeritics TriStar II 3020 - SPC Report Variables; Regression Chart Variables

TriStar II 3020 Appendix C
302-42828-01 - 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 li
ne 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.)