When this is done, the most essential factors for the analysis are graphically apparent, and in an orderly format. Histograms provide a simple, graphical view of accumulated data, including its dispersion and central tendency. In addition to the ease with which they can be constructed, histograms provide the easiest way to evaluate the distribution of data. Thus, given a particular effect, the diagram is constructed to identify and organize possible causes for it. Each major branch of the diagram corresponds to a major cause that directly relates to the effect.
Minor branches correspond to more detailed causal factors.
This type of diagram is useful in any analysis, as it illustrates the relationship between cause and effect in a rational manner. A time sequence chart showing plotted values of a characteristic. A common diagram of this type usually displays points representing the observed value of one variable corresponding to the value of another variable. Thus, it helps determine whether or not a process is operating consistently or if a special cause has occurred to change the process mean or variance. The bounds of the control chart are marked by upper and lower control limits that are calculated by applying statistical formulas to data from the process.