Lean Supply Chain Management Essentials

QuaLIty ControL 177

of defects produced. It is often useful to accompany a scatter diagram with a correla-

tion analysis to help determine the strength of the relationship of the two variables.

Histogram: A graph of contiguous vertical bars representing a frequency distribution in

which the groups or classes of items are marked on the x axis and the number of items in

each class is indicated on the y axis. e pictorial nature of the histogram lets people see

patterns that are difficult to see in a simple table of numbers.

—APICS Dictionary, 12th edition

A histogram (Figure9.6) highlights the center of the data as well as the amount

of variation ...