Welcome to lecture 29. This is again a part of previous lectures, the graphical methods of describing data. In this, we are going to study about the important Six Sigma tool, the Pareto analysis. Wilfred Pareto, an Italian economist conducted a study on distribution of national wealth in the year 1892 found that 80% he found that 80% of nation's wealth was worth 20% of population later adopted Iran identified that it is a universal phenomena rather than a mere economic phenomena. For example, 80% of company's business come from 20% of their customers 75% of problems are caused by 25% of causes, etc. Duran started using this philosophy to study ranked comparison of factors related to a quality problem.
This rule also known as 8020 rule, by Pareto analysis, we separate a set of causes into many Major and Minor categories. Dr. Duran named them as vital few and useful many respectively. After Pareto analysis, the team focuses on vital few contributing factors. For radio diagram is a presentation technique to let us learn how to construct a Pareto diagram with an example to find out the vital few contributors of waste during a yarn manufacturing process. The various categories of waste are as depicted in the table Namely Duffing wiping, breaks, upset and so on. And their respective quantities of waste in metric ton is also collected.
As first step of Pareto analysis, we have to find out the total effect of all the categories, here it comes as 140 metric ton. Next, arrange the data in descending order and find out the percentage of waste to the total for each category of waste. Then add each individual percentages to find out The cumulative percentage. Now, we could identify the vital few contributors with this step itself the three categories of waste that amounts to the 75 or 80 percentages of total effect, such as great piping and upsets. However, Pareto analysis is not finished, until we make the vital few contributors visible graphically. It is a global accepted quality tool for presentation to top management that is learn how to plot the Pareto analysis.
Draw a rectangular box first, then at the left hand side plot the wastage in metric ton. And at the right hand side the cumulative percentages of waste at the x axis plot the categories that contribute to the waste. Now plot each categories accordingly to their contribution to the total effect. Now, draw the points at cumulative percentage for each category boxes and join them with a line find out the vital few categories that contributes around 70 to 80% percentage of total effect name them as vital few categories that needed deep analysis further all of the categories are termed as useful many these clauses are attacked later, once the vital few causes have been eliminated completely. drawing up a rattle analysis manually is not a difficult task. When we have a relatively short list of categories or even by looking at the table itself, we may be able to identify the vital few causes.
But when we have say 100 of cat agrees drawing Pareto diagram manually becomes a tedious job or a tedious task Minitab comes to our help at such situations download and double click the file. Pareto analysis. The file consists of two sets of measurement data reasons for defects and its frequency, process steps and time taken in some manufacturing units. Let us conduct the Pareto analysis for defects. Click Start quality tools Pareto chart Pareto chart dialog box will open click chart defect table button type defects, reason at the box named labels in and number of defects in the box named frequencies in Pareto chart graph window opens now, analyze the graph by identifying the vital few causes that contribute to 80% of defects. Try to solve these reasons First, instead of concentrating on whole reasons.
That's all for this lecture. Pareto analysis is very simple and most accepted quality tool by global professionals you can try applying this tool at your processes. Now. Let us now proceed to the last part of this graphical methods lecture. Thank you