5

Symbols and Notations

x

i

absolute value of x

i

C

p

a capability ratio

C

pk

a centered capability ratio

LSL

lower specification limit

n

the number of items in a subgroup

s

the standard deviation of a sample

s²

the variance of a sample

the standard deviation for a theoretical population of

measurements

the approximate standard deviation for a theoretical population of

measurements

2

the variance of a theoretical population of measurements

USL

upper specification limit

x

i

the summation of all x

i

’s

X

the average of a set of data

x

i

a single measurement