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in control process

Upper

Specification

Limit (USL)

Lower

Specification

Limit (LSL)

6. Effects of variability on the process

Mean



•

A normal distribution is fully characterized with only two parameters:



The

mean

: information on process’

position.



The

standard deviation



: information on process’

dispersion

2 causes increasing the proportion of

data out of the specification limits



monitor their evolution

Part 1

Introduction to

SPC

Part 2

Essential

concepts to

start with SPC

Part 4

Conclusion

Part 3

SPC in

practice

NALYZE

Séri

Dispersion drift

Mean drift

03/10/17