12 Chapter 1 IntroduCtIon to data MInIng
the information present in the obtained data. These two techniques have
been successfully applied to medical data analysis, decision making in busi-
ness, industrial design, voice recognition, image processing, and process mod-
eling and identification.
For applications with a great deal of invalid data, it is often difficult to know
exactly which features are relevant, important, and useful for the given tasks.
Furthermore, certain attributes in the dataset may be undesirable, irrelevant,
or unimportant. Some tuples may even contain redundant information. The
number of attributes used by practical applications is often greater than 20, and
the number of tuples is often greater than several hundred ...