Question

Mr. Zeller chose a random group of 8 seventh-grade students. He asked them to write down the amount of money left in their school lunch accounts. Their responses are listed below.

$25.00, $34.60, $31.75, $14.10, $19.50, $20.50, $8.75, $13.80

What inference can Mr. Zeller make by using this sample?


All of the seventh-grade students have more than $10 in their lunch accounts.


Half of the students in the seventh grade have at least $20.00 in their lunch accounts.


The mean amount in the lunch accounts of seventh graders is $24.00.


One seventh-grade student has more than $35 in his or her lunch account.

Answer 1

Answer: "Half of the students in the seventh grade have at least $20.00 in their lunch accounts."

Reason: In the random sample 4 of the 8 students (25.00, 34.60, 31.75, 20.50) have at least $20, i.e. half the sample. The sample mean is 168/8 = $21.00 (not $24.00), there are no sampled accounts over $35, and a sample of 8 cannot guarantee every seventh‑grader has more than $10.