## Histograms

Our SPC software, SPC for Excel, easily constructs and updates histograms based on data in an Excel spreadsheet. A histogram is a bar chart that provides a snapshot in time of the variation in a process. It tells us how often a value or range of values occurred in a given time frame. A histogram will tell us the most frequently occurring value (the mode), the overall range, and the shape of the distribution (e.g., bell-shaped, skewed, bimodal, etc.). It is best to have 50 to 100 data points to construct a histogram, if possible. This program will construct a histogram from the raw data. It will automatically determine the number of classes (bars) as well as the class width. The options available in our SPC software are given below. These include the opportunity to change the number of classes, the class width, and the starting lower bound.

For more information on histograms, please see our December 2005 and January 2006 newsletters on histograms on our website. Need to teach histograms?  We also offer a complete teachning guide on histograms that you can easily customize.

### Histogram Options

• Changing the number of classes
• Changing where the histogram begins (lower bound)
• Changing the width of the classes
• Viewing the frequency distributions
• Easy updating of an existing histogram when new data is entered

If you select the option to display the descriptive statistics, the software will produce a box to the right of the histogram (as shown above) with the following information:

• Mean
• Standard Error
• Median
• Standard Deviation
• Variance
• Sum
• Count
• Maximum
• Minimum
• Range
• Kurtosis
• Skewness

If you want to change the number of classes, where the histogram starts or the width of the classes, select the classes button in the upper left hand part of the histogram and you will get the following input form with your options:

You can view the frequency distribution by selecting the "Freq. Dist" button on the histogram. The frequency distribution for this histogram is shown below.

### SPC for Excel

Our SPC software, SPC for Excel, provides an easy way to perform statistical analysis in Microsoft Excel. This SPC software is very cost effective and user-friendly.

At the same time, it is a very powerful statistical package that meets the needs of most professionals - green belts, black belts, quality professionals, quality assurance, front-line personnel, supervisors, quality control, controllers, engineers, and laboratory personnel - anyone who wants to improve their data analysis.

### Overview of SPC for Excel

At only \$189 for a single user, SPC for Excel is an attractive alternative for many organizations. It is the perfect tool to use for statistical analysis, process improvement, problem solving and statistical training. Our SPC software is used internationally in over 60 countries. You also receive regular revisions to your version with no maintenance fees!  And we have great discounts for multiple users!

The software includes control charts, Pareto diagrams, histograms, scatter diagrams, fishbone diagrams, process capability analysis, measurement systems analysis, regression, experimental design, hyptoheses testing, nonparametric analysis and much more.    The software works with Excel 2000 through Excel 2010.

The links below provide more details on the SPC for Excel software.

Statistical Tools in SPC for Excel

Demo