Question

Define support and confidence in data mining

Answer 1

The confidence interval (CI) establishes the range (high sales level +/- CI) within which the corresponding predicted output (i.e., sales) per combination of the inputs (i.e., demographics) occurs 95% of the time. The higher the CI, the less predictive, and therefore useful, the model.

Support: Support of a rule is a measure of how frequently the items involved in it occur together. Using probability notation: support (A implies B) = P(A, B).
Confidence: Confidence of a rule is the conditional probability of B given A. Using probability notation: confidence (A implies B) = P (B given A).