What Do These Histograms Tell You?

Our previous blog introduced histograms. Histograms tell you four things about your process. Remember what those were? If not, see our previous blog, What is a Histogram? . Histograms also can give you insights to things you might not normally see. The example below demonstrates this.

Here is the background information for you. A supplier sends in weekly shipments of one raw material to you. There is one raw material characteristic that is key to how it performs in your process. The supplier provides you with a Certificate of Analysis with...


What is a Histogram?

A histogram is a snapshot in time of your process. It tells you four things:

  • Which result (or range of results) occurs most frequently
  • How much variation there is
  • What the shape of the variation looks like
  • If any results are out of specifications

Remember, all processes have variation. Processes in statistical control tend to form a stable pattern, which is called a distribution. Distributions are characterized by three parameters: location, spread, and shape. These parameters can be estimated from a histogram. An example of a...

What is a Pareto Chart?

A Pareto chart helps you answer questions. What is the reason for the most rework or scrap in your organization? Which customers complain the most? What keeps us from getting the books closed after the end of the month. These questions are common in organizations, but we don’t always agree on the answer. This is where the Pareto chart comes in. A Pareto chart is a data-based approach to determining what “vital few” issues you should be working on.

The Pareto chart is named after Vilfredo Pareto, an Italian economist, who discovered that 80% of Italy’s wealth was held by 20% of the...

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