5) Classify each sampling technique as random, systematic, stratified, or cluster. a) In a large school district, all teachers from two buildings are interviewed to determine whether they believe the students have less homework to do now than in previous years. b) Every seventh customer entering a shopping mall is asked t select his or her favorite store. c) Nursing supervisors are selected via random number generation to determine annual salaries. d) Every 100th hamburger manufactured by a meat-packing company is checked to determine its fat content and compliance with hygiene laws. e) Mail carriers of a large city are divided into four groups according to both their gender and according to whether they walk or ride on their routes. Then 10 are selected from each group and interviewed to determine whether or not they have been bitten by a dog in the last year.