histogram

Three Rules for Data Analysis: Plot the Data, Plot the Data, Plot the Data

The job of any purchasing department is to source for reliable suppliers who deliver products conforming to specification on time and within a certain price range. The more data is available about potential suppliers, the better the decision will be. The question is, how should that data be analyzed? The following case study helps to…

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Histogram

Kerri Simon

Purpose of a Histogram A histogram is used to graphically summarize and display the distribution of a process data set. How to Construct a Histogram A histogram can be constructed by segmenting the range of the data into equal sized bins (also called segments, groups or classes). For example, if your data ranges from 1.1 to 1.8,…

Proper Data Granularity Allows for Stronger Analysis

Michael Ohler

Can we trust the data? This is the fundamental question behind measurement system analysis (MSA). The question can come up in any data-based project. Shortcomings in a measurement system’s accuracy (bias, linearity, stability or correlation) and precision (resolution, repeatability or reproducibility) can obstruct analysis purposes. One often-overlooked aspect of resolution is data granularity, or the…

Interpreting Anomalies Correctly Can Help Avoid Waste

Peter J. Sherman

People say that Six Sigma is sometimes like using a rocket ship engine in an automobile. The techniques and statistical software tools are so powerful they can lead to anomalies in the data or produce “bad” results. These include: Histograms that do not appear normal Scatter plot diagrams that do not fit a straight line…

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