Word “Data” is derived from Latin word “Dare” whichmeans “to give”.
Data is the foundation on which information and knowledge arebuilt. Data can be categorized, measured and represented. Data is usuallyrepresentative in nature. Data can take various forms, such as number,character, symbol, sound, image, waves of different frequency. Further throughraw data information is implied and knowledge is derived. Data can be recordedand stored either in analogue or digital form.
Individually separate, distinctin nature, aggregative, diverse in their characteristic, ease ofunderstandability and comprehensiveness improves quality of data. The two-broad classification of data: qualitative andquantitative. Qualitative data consists of numeric records. They are generallyphysical properties (height, weight, length, width, area). They data isanalyzed through visualizations, descriptive and inferential statistics.
Qualitative data are non-numeric. They are texts, pictures, sounds, videos.They are analyzed through machine learning & data mining techniques.Based on structure data is categorized as: structured,semi-structured and unstructured. Structured data are those which can be easilyorganized, stored and transferred into various data models. Semi-structureddata are loosely structured data which does not have a predefined model orschema.
They are irregular and often nested hierarchically, but have reasonablyconsistent fields, provides self-defining content metadata and a means tostructure data. Unstructured data do not have a data model or structure. Theycannot be easily combined or computed.
By its origin data can also be classified as: Captured(data collected directly through survey or experiment); Exhaust (data collectedthrough a device, system); Transient (data which are never processed orexamined); Derived (data generated or processed from a system set). Other classification of data: Generated data is calledprimary data whereas data made available for analysis is called secondary data.Derived data are called tertiary data. Data which act as unique identifiers arecalled indexical data.
Data representing a phenomenon are called attribute dataand data about data is a metadata.