Maria wants to determine which student is favored for president of the student council. Which of the following samples are biased and not random? Select all that apply.

A sample is biased when it systematically leaves out parts of the student body or focuses on a group that may have a particular preference. Surveying only freshman boys, only students in Maria’s math class, or only chess club members does not represent all students and may favor certain candidates. Surveying every other student in the cafeteria and randomly choosing 20 students from each grade are broader sampling methods, so they are not necessarily biased.

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