2.1. Histogram
A histogram is one of the basic quality
tools. It is used to graphically summarize and
display the distribution and variation of a process
data set. A frequency distribution shows how often
each different value in a set of data occurs. The
main purpose of a histogram is to determine the
shape of data set. We can present the same
information in a table; but the graphic presentation
shows relationship. Based on the frequency of
distributed values, one can come to a conclusion
whether the values falls within the specified values
and gives a normal distribution curve out of it. [3]
This can be achieved by Histogram. It is a useful
tool for breaking out process data into regions for
determining frequencies of certain events or
categories of data.
Typical applications of histograms in root cause
analysis include: