User`s manual

Standard Deviation

The formula for calculating the standard deviation of a

subgroup (sample) is:

s =

A$- (g&)*/n

i=l

(n- 1)

s Bar

The formula for calculating the mean of a series of standard

deviation values (s) is:

s = izl

Estimated Sigma: X Bar and R Chart

The formula for calculating estimated sigma (a) for the X

Bar and R chart is:

estimated CJ = d

Estimated Sigma: X Bar and s Chart

The formula for calculating estimated sigma (CT) for the X

Bar and s chart is:

estimated u = L

c-3