1. The following dataset gives all the previous customers a store had. The dataset shows their age, status (student/not student), credit history, and whether they buy or no:

I.A) Construct a classification tree based on customers database and calculate the purity for each node (Gini Index formula is provided in the appendix section in page 6). Provide your answer in the next page.

I.B) Based on the constructed tree in section I.A, classify the following data (provide your answers in the table):

Age	Student	Credit Rating	Buy?
Middle-aged	Yes	Excellent
Senior	No	Excellent
Young	No	Fair