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1.
Exploratory Data Analysis
1.1. EDA Introduction
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| Approach |
Exploratory Data Analysis (EDA) is an approach/philosophy for data
analysis which employs a variety of techniques (mostly graphical) to
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| Focus | The EDA approach is precisely that--an approach--not a set of techniques, but an attitude/philosophy about how a data analysis should be carried out. | ||
| Philosophy | EDA is not identical to statistical graphics although the two terms are used almost interchangeably. Statistical graphics is a collection of techniques--all graphically-based and all focusing on one or another data characterization aspect. EDA encompasses a larger venue; EDA is an approach to data analysis which postpones the usual assumptions about what kind of model the data follow with the more direct approach of allowing the data itself to reveal its underlying structure and model. EDA is not a mere collection of techniques; EDA is philosophy as to how we disect a data set; what we look for; how we look; and how we interpret. It is true that EDA heavily uses the collection of techniques that we call "statistical graphics", but is not identical to statistical graphics per se. | ||
| History | The seminal work in EDA is Exploratory Data Analysis, Tukey, (1977). Over the years it has benefitted from other noteworthy publications such as Data Analysis and Regression, Mosteller and Tukey (1977), Interactive Data Analysis, Hoaglin (1977), The ABC's of EDA, Velleman (1981) and has gained a large following as "the" way to analyze a data set. | ||
| Techniques |
Most EDA techniques are graphical in nature with
a few quantitative techniques. The reason for the heavy reliance on
graphics is that by its nature the main role of
EDA is to open-mindedly explore, and graphics
gives the analysts unparalleled power in terms of
such open-mindedly exploration, enticing the data to
reveal its structural secrets, and being ever-ready to
gain some new--often unsuspected--insight into
the data. In combination with the natural pattern-recognition
capabilities that we all possess, graphics provides, of course,
unparalleled power to carry this out.
The particular graphical techniques employed in EDA are often quite simple consisting of various techniques of:
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