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

   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?

   • the miles ridden on Saturday
   • all 10 riders in the bike club
   • the 4 riders Tala timed
   • all the riders in the state
3. 3.

   Jun wants to learn about every pet snail in the science room but times only 3 of them. No snail was rushed. Which choice names the sample, the part that was picked?

   • the 3 pet snails Jun timed
   • all 8 pet snails in the science room
   • all the snails in the world
   • the centimeters crawled in a minute
4. 4.

   Picture each of the 240 students as one dot on a dot plot. The sample is the 8 dots picked. Pia wants to know how many minutes the 240 students at Maple School read each night, and can ask 8 students. Which way of choosing gives a sample that fairly shows all 240?

   • Draw 8 names from a hat holding all 240 student names.
   • Ask the 8 students who sit closest to the classroom door.
   • Ask the 8 students who belong to the school book club.
   • Ask the first 8 students who volunteer to answer.
5. 5.

   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?

   • Ask the 10 students who ride bus number 4.
   • 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 live on Bo's street.

6. 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.

7. 6.

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