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Office of Performance Improvement (OPI)
Histogram
Jump To: How To | Examples | More Information | Print this Page (PDF)
Histograms summarize process data over a period of time, and present frequency in the form of a bar graph. 
A histogram:
- Displays large amounts of data in visual format
- Shows relative frequency of various data values
- Illustrates underlying distribution of the data
- Reveals the shape and variation of the data
- Provides information for predicting future performance
| How to Construct a Histogram |
Creating a Histogram
- Decide on the indicator to be measured
- Collect at least 50 data points
- Prepare a frequency table from the data
- Group the data into intervals
- Create the histogram
Interpreting a Histogram
- Consider where the distribution is centered
- Analyze the variation and spread of the data
- Look at the shape of the distribution
- Consider these factors in the context of targets
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Examples of Histograms
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| Further Reading |
More Information
- PQ Systems: Histogram (PDF: 51KB / 6 pages)
- McCoy: Finding the Right Tool for your Purpose
(PDF: 466KB / 40 pages)
Source
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