From the course: Lean Six Sigma: Define and Measure Tools

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Variation: Dotplot, histogram, boxplot

Variation: Dotplot, histogram, boxplot

From the course: Lean Six Sigma: Define and Measure Tools

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Variation: Dotplot, histogram, boxplot

“

- You have two suppliers, A and B. They are supposed to deliver within 24 hours. They both report the same average delivery time of 23 hours. Are they performing well? It's difficult to tell with only this information. We have to go beyond just one number, such as the mean. We have to plot the data to see the variability or variation in delivery times. We need graphs that display variation. For continuous data, graphs and charts commonly used in Lean Six Sigma projects are dotplots, histograms, and boxplots. These graphs display the pattern of variation, showing how spread out the measurements are and where they are centered. Here we have dotplots showing the delivery times of the two suppliers, A and B. Each dot shows a data point. And the horizontal axis is the time scale in hours. We can see that while both have a mean of 23 hours, there is a lot more variation in A, with many deliveries exceeding 24 hours. On the other hand, B is more consistent than A, so consistent that B did…

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