Validation Set
A set of examples used to tune the parameters of a classifier, for example to choose the number of hidden units in a neural network.
Extent to which a measure or set of measure correctly represents the concept of study-the degree to which it is free from any systematic or nonrandom error. Validity is concerned with how well the concept is defined by the measure(s), whereas reliability relates to the consistency of the measure(s).
One of the most popular orthogonal factor rotation methods.
  Vector Quantization
A method of encoding data for signal transmission, in which a vector is replaced by one of a finite number of representatives.