Exploratory data analysis (EDA) relies heavily on such techniques. They can also provide insight into a data set to help with testing assumptions,model selection andregression model validation, estimator selection, relationship identification, factor effect determination, andoutlier detection. In addition, the choice of appropriate statistical graphics can provide a convincing means of communicating the underlying message that is present in the data to others.[1]
Graphical statistical methods have four objectives:[2]
The exploration of the content of a data set
The use to find structure in data
Checking assumptions in statistical models
Communicate the results of an analysis.
If one is not using statistical graphics, then one is forfeiting insight into one or more aspects of the underlying structure of the data.
Statistical graphics have been central to the development of science and date to the earliest attempts to analyse data. Many familiar forms, includingbivariate plots,statistical maps,bar charts, andcoordinate paper were used in the 18th century. Statistical graphics developed through attention to four problems:[3]
Spatial organization in the 17th and 18th century
Discrete comparison in the 18th and early 19th century
Continuous distribution in the 19th century and
Multivariate distribution and correlation in the late 19th and 20th century.
Since the 1970s statistical graphics have been re-emerging as an important analytic tool with the revitalisation ofcomputer graphics and related technologies.[3]
William Playfair's trade-balance time-series chart, published in hisCommercial and Political Atlas, 1786John Snow's Cholera map in dot style, 1854
Famous graphics were designed by:
William Playfair who produced what could be called the firstline,bar,pie, andarea charts. For example, in 1786 he published the well known diagram that depicts the evolution ofEngland's imports and exports,[4]
James Watt and his employeeJohn Southern, who around 1790 inventedthe steam indicator, a device for plotting pressure variations within a steam engine cylinder through its stroke,[5]
Florence Nightingale, who used statistical graphics to persuade the British Government to improve army hygiene,[6]
John Snow who plotted deaths fromcholera inLondon in 1854 to detect the source of the disease,[7] and
This article incorporatespublic domain material from the National Institute of Standards and Technology
