Wiley - Data Mining with Microsoft SQL Server 2008 (2009)02 | Introduction to Data Mining in SQL Server 2008 3 Figure 1-1 Student table In contrast the data mining approach for this problem is almost the reverse of the query-and-explore method. Instead of guessing a hypothesis and trying it out in different ways you ask the question in terms of the data that can support many hypotheses and allow your data mining system to explore them for you. In this case you indicate that the columns IQ Gender Parentincome and ParentEncouragement are to be used as hypotheses in determining Collegeplans. As the data mining system passes over the data it analyzes the influence of each input column on the target column. Figure 1-2 shows the hypothetical result of a decision tree algorithm operating on this data set. In this case each path from the root node to the leaf node forms a rule about the data. Looking at this tree you see that students with IQs greater than 100 and who are encouraged by their parents are highly likely to attend college. In this case you have extracted knowledge from the data. As shown here data mining applies algorithms such as decision trees clustering association time series and so on to a data set and then analyzes its contents. This analysis produces patterns which can be explored for valuable information. Depending on the underlying algorithm these patterns can be in the form of trees rules clusters or simply a set of mathematical formulas. The information found in the patterns can be used for reporting to 4 Chapter 1 Introduction to Data Mining in SQL Server 2008 guide marketing strategies for instance and for prediction. For example if you could collect data about undecided students you could select those who are likely to be interested in continued education and preemptively market to that audience. Figure 1-2 Decision tree Business Problems for Data Mining Data mining techniques can be used in virtually all business applications answering various types of businesses questions. In truth given the software .
