Does this sample fairly show the whole group?

Answer Key - Grade 7 Math Worksheet - Building Confidence

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

1. 1.

   Ari wants to learn about every tomato plant in the school bed but measures only 3 of them. One tomato plant leaned toward the camera. Which choice names the population, the whole group?

   • the 3 tomato plants Ari measured
   • all 9 tomato plants in the school bed
   • all the tomato plants in town
   • the heights in inches
2. 2.

   Luz wants to learn about every member of the piano club but measures only 3 of them. The piano was not available for comment. Which choice names the population, the whole group?

   • the minutes of practice a week
   • all the piano clubs in the county
   • all 8 members of the piano club
   • the 3 piano club members Luz measured
3. 3.

   Tala wants to learn about every rider in the bike club but times only 4 of them. A bike bell rang at the wrong moment. Which choice names the sample, the part that was picked?

   • all the riders in the state
   • all 10 riders in the bike club
   • the 4 riders Tala timed
   • the miles ridden on Saturday
4. 4.

   Picture each of the 150 students as one dot on a dot plot. The sample is the 10 dots picked. Bo wants to know how long the 150 seventh graders take to get to school, and can ask 10. Which way of choosing gives a sample that fairly shows all 150?

   • Number all 150 students and pick 10 numbers at random.
   • Ask the 10 students who sign up on a sheet.
   • Ask the 10 students who ride bus number 4.
   • Ask the 10 students who live on Bo's street.

5. Read this first

   Use this

   Picture each of the 90 bean plants as one dot on a dot plot. The sample is the 9 dots picked.

6. 5.

   Milo wants to know how tall the 90 bean plants in the school garden are, and can measure 9. Which way of choosing gives a sample that fairly shows all 90?

   • Measure the 9 plants the gardener says look best.
   • Draw 9 plant tags from a bag holding all 90 tags.
   • Measure the 9 plants closest to the garden path.
   • Measure the 9 plants in the sunniest row.
7. 6.

   Picture each of the 200 players as one dot on a dot plot. The sample is the 10 dots picked. Zee wants to know how many minutes the 200 players in a school band practice each week, and can ask 10 players. Which way of choosing gives a sample that fairly shows all 200?

   • Give every player a number and let a random-number tool pick 10.
   • Ask the 10 players who are in the band room right now.
   • Ask the 10 players who answer Zee's note.
   • Ask the 10 players who sit in the first chairs.
8. 7.

   Kira measured all 8 sunflowers, then picked the 3 tallest. One leaned toward the camera. How far is the mean of the 3 picked from the mean of all 8?

   6.5
9. 8.

   Ren measured all 8 runners, then picked the 3 fastest. Nobody tripped over a shoelace. How far is the mean of the 3 picked from the mean of all 8?

   2
10. 9.

    Esme measured all 8 students, then picked 4 cards from a shuffled set of 8. The jump rope tangled itself. How far is the mean of the 4 picked from the mean of all 8?

    0.5
11. 10.

    Noah measured all 8 leaves, then picked 4 tags from a bag of 8. A squirrel supervised. How far is the mean of the 4 picked from the mean of all 8?

    0.5