Quantitative association rules may disclose exceptional behaviors within a data set, where exceptional can be defined based on statistical theory. For example, Section 7.2.3 shows the association rule sex = female ? mean wage = $7.90/hr (overall mean wage = $9.02/hr), which suggests an exceptional pattern. The rule states that the average wage for females is only $7.90 per hour, which is a significantly lower wage than the overall average of $9.02 per hour. Discuss how such quantitative rules can be discovered systematically and efficiently in large data sets with quantitative attributes.