Exercise 11: Classify the sampling technique ( random, stratified, systematic, cluster) used to get the following samples. 1. Every 12th costumer entering a shopping mall is asked to select his or her favorite store. 2. In a university, all teachers from three buildings are interviewed whether they believe the students have higher grades now than in previous years. 3. Supervisors are selected using random numbers in order to determine annual salaries. 4. A teacher writes the name of each student in a card, shuffles the card, and then draws five names. 5. A head nurse selects 10 patients from each floor of a hospital