Histograms show counts or density of a measure, which is then discretized (binned) to make counting meaningful. They are best used to observe the distribution of the measure. They are sometimes confused with plain bar charts, which can be modified to show counts but usually encode the measure value as the length of the bar.
Let's use the sample file, Sample – Superstore Sales (Excel)
. Open a new worksheet and select Sample – Superstore Sales (Excel) as the data source.
Once the data is loaded, perform the following steps to create a histogram:
Histograms are very effective charts in observing the distribution of the measure of interest; however, sometimes the distribution is quite skewed or centered at one range or position, and in such cases rebinning (creating different bins is covered later in Chapter 6, Calculating User-defined Fields, in the Discretizing data recipe) assists the reader in observing the detailed distribution or uncovering some patterns.