Page 170 - The Handbook for Quality Management a Complete Guide to Operational Excellence

156 P r o c e s s C o n t r o l Q u a n t i f y i n g P r o c e s s Va r i a t i o n 157

Mode
Mean

Mean = Median = Mode
Skewness = 0 Skewness = +1
Figure 9.1 Illustration of mean, median, and mode.

µ = 0, σ = 1

µ = 0, σ = 2

Figure 9.2 Illustration of sigma.

K = +1 K = 0 K = –1

Figure 9.3 Illustration of skewness.

β = 4.5
2
β 2 = 3.0
β = 1.0
2

Figure 9.4 Illustration of kurtosis.

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