Editing Histogram (section)

[[File:Black_cherry_tree_histogram.svg|thumb|In this histogram, height is divided into bins of equal width (5 feet)]]
{{Short description|Graphical representation of the distribution of numerical data}}
{{Hatnote|For the histogram used in digital image processing, see [[Image histogram]] and [[Color histogram]].}}

A '''histogram''' is a visual representation of the [[frequency distribution|distribution]] of quantitative data. To construct a histogram, the first step is to [[Data binning|"bin" (or "bucket")]] the range of values— divide the entire range of values into a series of intervals—and then count how many values fall into each interval.  The bins are usually specified as consecutive, non-overlapping [[interval (mathematics)|intervals]] of a variable. The bins (intervals) are adjacent and are typically (but not required to be) of equal size.<ref>{{cite book |last1=Howitt |first1=D. |last2=Cramer |first2=D. |year=2008 |title=Introduction to Statistics in Psychology |publisher=Prentice Hall |edition=Fourth |isbn=978-0-13-205161-3 }}</ref>

Histograms give a rough sense of the density of the underlying distribution of the data, and often for [[density estimation]]: estimating the [[probability density function]] of the underlying variable. The total area of a histogram used for probability density is always normalized to 1. If the length of the intervals on the ''x''-axis are all 1, then a histogram is identical to a [[relative frequency]] plot.

Histograms are sometimes confused with [[bar chart]]s. In a histogram, each bin is for a different range of values, so altogether the histogram illustrates the distribution of values. But in a bar chart, each bar is for a different category of observations (e.g., each bar might be for a different population), so altogether the bar chart can be used to compare different categories. Some authors recommend that bar charts always have gaps between the bars to clarify that they are not histograms.<ref>{{cite web |last1=Naomi |first1=Robbins |title=A Histogram is NOT a Bar Chart |url=https://www.forbes.com/sites/naomirobbins/2012/01/04/a-histogram-is-not-a-bar-chart/#345b9c746d77 |work=Forbes |access-date=31 July 2018}}</ref><ref>{{cite journal
| author  = M. Eileen Magnello
| date    = December 2006
| title   = Karl Pearson and the Origins of Modern Statistics: An Elastician becomes a Statistician
| journal = The New Zealand Journal for the History and Philosophy of Science and Technology
| volume  = 1 volume
| oclc    = 682200824
| url     = http://www.rutherfordjournal.org/article010107.html
}}
</ref>