What role do labor unions play in resolving disputes? A. They tend to favor certain candidates.
B. They conduct research on issues and opinions.
C. They represent members in negotiations.
D. They conduct voter education programs.
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Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling