Does this sample fairly show the whole group?

Answer Key - Grade 7 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Luz took two samples of 4 from 10 bean plants. A is the 4 tallest; B was drawn from a bag. How much closer to the mean of all 10 is B's mean than A's?

   4.5
2. 2.

   Tala took two samples of 4 from 10 bus rides. A is the 4 shortest; B was drawn from a bag. How much closer to the mean of all 10 is B's mean than A's?

   5.5
3. 3.

   Jun took two samples of 4 from 10 kites. A is the 4 longest flights; B was drawn from a bag. How much closer to the mean of all 10 is B's mean than A's?

   3.5
4. 4.

   Pia took two samples of 4 from 10 backpacks. A is the 4 lightest; B was drawn from a bag. How much closer to the mean of all 10 is B's mean than A's?

   3.5
5. 5.

   Picture each of the 400 students as one dot on a dot plot. A sample is the dots picked. Bo wants to know how many hours the 400 students at Cedar School spend on screens each day. Which plan gives the sample more likely to fairly show all 400?

   • Ask all 80 students in the gaming club.
   • Draw 12 names from a hat holding all 400 names.
   • Ask the 60 students who fill out a form.
   • Ask the 100 students who stay after school today.
6. 6.

   Picture each of the 260 students as one dot on a dot plot. A sample is the dots picked. Milo wants to know how many books the 260 students at Harbor School read in a month. Which plan gives the sample more likely to fairly show all 260?

   • Ask all 40 students in the library club, since they love reading
   • Ask the 35 students who sign a sheet.
   • Draw 13 names from a hat holding all 260 names.
   • Ask the 50 students nearest the book fair.
7. 7.

   Picture each of the 350 students as one dot on a dot plot. A sample is the dots picked. Kira wants to know how many pets the 350 students at Hill School have at home. Which plan gives the sample more likely to fairly show all 350?

   • Ask the 75 students in the first lunch line, since they are easy to find
   • Draw 14 names from a hat holding all 350 names.
   • Ask the 45 students who vote online.
   • Ask the 60 students in the animal club.
8. 8.

   Picture each of the 40 members as one dot on a dot plot. The sample is the 8 dots picked. Ren drew 8 names at random from the 40 art club members and asked about weekly homework hours. The sample mean was 5 hours. Which conclusion does the sample support?

   • The sample suggests every art club member spends exactly 5 hours a week on homework; it is only a guess, not proof.
   • The sample suggests art club members spend about 5 hours a week on homework; it is only a guess, not proof.
   • The sample suggests nothing about the art club, because it asked only 8 of 40 members; it is only a guess, not proof.
   • The sample suggests all students at the school spend about 5 hours a week on homework; it is only a guess, not proof.
9. 9.

   Esme drew 6 names at random from the 30 chess club members and asked about weekly chess hours. The sample mean was 4 hours. Which conclusion does the sample support?

   • The sample suggests chess club members spend about 4 hours a week on chess; it is only a guess, not proof.
   • The sample suggests nothing about the chess club, because it asked only 6 of 30 members; it is only a guess, not proof.
   • The sample suggests all students at the school spend about 4 hours a week on chess; it is only a guess, not proof.
   • The sample suggests every chess club member spends exactly 4 hours a week on chess; it is only a guess, not proof.
10. 10.

    Picture each of the 36 members as one dot on a dot plot. The sample is the 6 dots picked. Noah asked the first 6 of the 36 track team members to arrive how many laps they run. The sample mean was 8 laps. Which conclusion does the sample support?

    • The sample suggests all students at the school run about 8 laps; it is only a guess, not proof.
    • The sample suggests every track team member runs exactly 8 laps; it is only a guess, not proof.
    • The sample suggests little about the track team, because the first to arrive may not be typical; it is only a guess, not proof.
    • The sample suggests track team members run about 8 laps; it is only a guess, not proof.