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

   Picture each of the 500 students as one dot on a dot plot. A sample is the dots picked. Zee wants to know how many hours the 500 students at Lake School sleep on school nights. Which plan gives the sample more likely to fairly show all 500?

   • Ask the 70 students who return a note.
   • Ask the 120 students in the first lunch.
   • Pick 20 student numbers with a random-number tool.
   • Ask the 90 students on the sports teams, since they are easy to find
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 60 students in the animal club.
   • Ask the 45 students who vote online.
   • Draw 14 names from a hat holding all 350 names.
   • Ask the 75 students in the first lunch line, since they are easy to find
8. 8.

   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 all students at the school 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 every chess club member spends exactly 4 hours a week on chess; it is only a guess, not proof.
9. 9.

   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 every track team member runs exactly 8 laps; it is only a guess, not proof.
   • The sample suggests track team members run about 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 all students at the school run about 8 laps; it is only a guess, not proof.
10. 10.

    Picture each of the 50 members as one dot on a dot plot. The sample is the 8 dots picked. Ari asked the 8 students in the front row, out of 50 in the grade, how many books they read this month. The sample mean was 6 books. Which conclusion does the sample support?

    • The sample suggests all students in the district read about 6 books this month; it is only a guess, not proof.
    • The sample suggests every student in the grade reads exactly 6 books this month; it is only a guess, not proof.
    • The sample suggests little about the students in the grade, because front-row students may not be typical; it is only a guess, not proof.
    • The sample suggests students in the grade read about 6 books this month; it is only a guess, not proof.