Li designed a survey to determine how comfortable students at her middle school are with fractions. There are 600 students in her middle school. The students are equally distributed among grade levels. She selected a sample of 28 students in her first-period class. Which best explains Li’s sample?

Li chose 28 students from her own first-period class rather than selecting students randomly from all 600 students, so the sample is nonrandom. Students in that class may not represent students across the whole school, making the sample biased. The best choice is “nonrandom and biased.”

AI-written and checked against the verified answer.