An application example where global outliers, contextual outliers and also collective outliers are all interesting is credit card fraud detection. If a student’s credit card charges during the semester range from $100 to $150 but the student’s statement has one expenditure charge of $500, then the latter charge is a global outlier. If the student’s charges during the summer holidays range from $400 to $700, then the $500 spent during the semester is a contextual outlier because it is an interesting value when the period when it was spent is considered. Most of the student’s charges for the year fall between $100 to $150, hence the charges for the summer holidays, which range from $400 to $700 are collective outliers. The attributes include