User`s manual

Formulas -
Here is a list of the SPC formulas that are applicable to the
SPC option in the support software.
X Bar
The formula for calculating the mean of a series of
individual values (x) is:
n
X Double Bar
The formula for calculating the mean of a series of
subgroup means (T) is:
-
k
c
x= = i=,
x;
k
Range
The formula for calculating the range between the highest
and lowest values in a series of values (x) is:
R = x,--x,,
R Bar
The formula for calculating the mean of a series of range
values (R) is:
-
k
c
if = &,
Ri
k
c-2