A bar chart and a Pareto chart both use bars to show frequencies of categories of categorical data. What characteristic distinguishes a Pareto chart from a bar chart, and how does that characteristic help us in understanding the data?Choose the correct answer below.
A.In a Pareto chart, the bars depict cumulative frequencies. The Pareto chart helps us understand data by depicting cumulative frequencies instead of individual frequencies.
B.In a Pareto chart, the bars are always arranged on a nonzero axis. The Pareto chart helps us understand data by depicting the frequencies without reference to a zero point.
C.In a Pareto chart, the bars are always arranged in descending order according to frequencies. The Pareto chart helps us understand data by drawing attention to the more important categories, which have the highest frequencies.
D.In a Pareto chart, the frequencies are depicted as slices of a circle. The Pareto chart helps us understand data by representing frequencies as proportions of a circle.

The correct answer is C.In a Pareto chart, the bars are always arranged in descending order according to frequencies. The Pareto chart helps us understand data by drawing attention to the more important categories, which have the highest frequencies.

Explanation:

Vilfredo Pareto was an Italian engineer, economist, philosopher and sociologist who observed that in different social, natural, economic phenomena, etc., there was often a coincidental pattern in most cases. Given a specific problem, approximately 80% of the effects were caused by 20% of the causes. This statistical phenomenon was subsequently generalized and introduced, developed and popularized in the industrial field by Joseph Juran, called Pareto Principle.

The Pareto chart, based on this principle, consists of arranging the frequency bars in descending order to distinguish the few most important categories/ causes (to the left of the diagram) from the many less important categories/ causes (to the right of the diagram).

A complement to the bar chart used in the Pareto chart is a linear graph made up of the cumulative frequency of the different causes, making it possible to analyze more easily what the aggregate causes accumulate 80% of the accumulated effects. This allows defining the priorities in order to focus on attacking the main causes to obtain high impact results when implementing actions in order to solve the problem studied.

For example, in an industrial process you can classify the causes of failure of a machine from highest to lowest according to the minutes lost due to causes of each type of failure. The Pareto chart classifies the main causes of failure and implements actions to reduce or eliminate only the main failures. Once these failures have been resolved, the machine's time losses should be considerably reduced.