A histogram shows how many times a value occurs in a sample of data. This is represented on a graph (as shown below) by vertical bars, where each bar is a measure of the number of times the value occurs. Histograms are constructed by dividing the value range of the variable into what are called ‘bins’ – these are just ranges of values that the variable can assume. Histograms are frequently used to estimate probabilities by summing the occurrences over a certain range of values and dividing by the total number of data points.
Popular ways to construct histograms include:
Histograms are natively supported in Excel by specifying the bin range and various labels.
QI Macros (offer a free trial) provides sophisticated histogram types including: Bell Shaped plots, Capability statistics, Descriptive Statistics, Six Sigma statistics, one and two-sided specification limits.
Excel histograms can be imported into PowerPoint by employing the Analysis Toolpack in Excel. The histogram is copies from Excel and pasted into PowerPoint – it’s as simple as that.
Virtually all BI tools support histograms, and these are often used in dashboards. Free dashboard tools can be found in a separate article on this web site here.
D3 supports histograms.
Protovis is a graphical approach to visualisation and supports histograms.