Surveys, experiments and observational studies, and judging a report

Grade 11 Math Worksheet

Circle the best answer.

1. 1.

   Zee wants to know if music while studying changes quiz scores for the 60 students in a grade. Which plan answers the question best?

   • Compare scores of students who already study with music and those who do not.
   • Let each student choose music or quiet, then compare scores.
   • Assign the 60 students at random to music or quiet, then compare scores.
2. 2.

   Ari wants to know if a new plant food makes bean plants grow taller, using 40 bean plants. Which plan answers the question best?

   • Compare growth of bean plants whose owners already use plant food with those that do not.
   • Assign the 40 plants at random to plant food or plain water, then compare growth.
   • Let each plant's owner choose plant food or water, then compare growth.
3. 3.

   Bo wants to know what percent of the school's 900 students walk to school. Which plan answers the question best?

   • Ask the first 90 students who arrive at school in the morning.
   • Ask 9 students drawn at random from the full list.
   • Ask 90 students drawn at random from the full list of 900.
4. 4.

   Esme wants to know the mean hours of sleep of the district's 3,000 seventh graders. Which plan answers the question best?

   • Ask the 150 students in one school's early-morning club that meets daily.
   • Ask 15 seventh graders drawn at random from the list.
   • Ask 150 seventh graders drawn at random from the district list.
5. 5.

   Of 120 students Kira studied, those who read for fun tend to know more vocabulary words. What does the study show?

   • Reading for fun makes students learn more words.
   • It was an experiment, so reading for fun is the cause.
   • Reading for fun goes with knowing more words; the study cannot show it causes that.
6. 6.

   Luz's class assigned 44 bean plants at random to plant food or plain water; the plant-food group grew taller. What does the study show?

   • Plant food makes every kind of plant grow taller.
   • It shows only a link; it cannot show plant food made the difference.
   • The plant food likely made these bean plants grow taller.
7. 7.

   "Don't you agree the old library chairs are uncomfortable?" Sample: 200 names drawn at random from all 1,500 students. Noah checks the survey in the figure. What is its main problem?

   • The wording pushes students toward yes.
   • Nothing: the sample was random, so the result is fair.
   • The students were not drawn at random.
   • 200 students is too few to tell anything.
8. 8.

   "Should the school keep the fun, popular field day?" Sample: 150 names drawn at random from all 1,200 students. Pia checks the survey in the figure. What is its main problem?

   • The students were not drawn at random.
   • 150 students is too few to tell anything.
   • The wording pushes students toward yes.
   • Nothing: the sample was random, so the result is fair.
9. 9.

   "How many minutes did you read last night?" Sample: the 120 students at the library after school. Ren checks the survey in the figure. What is its main problem?

   • Students at the library may read more than others.
   • The wording pushes students toward one answer.
   • 120 students is too few to tell anything.
   • Nothing: the question is fair, so the result is fair.
10. 10.

    "Do you recycle at home?" Sample: the 80 members of the school's green club. Tala checks the survey in the figure. What is its main problem?

    • Nothing: the question is fair, so the result is fair.
    • 80 students is too few to tell anything.
    • The wording pushes students toward one answer.
    • Green club members likely recycle more than other students.