Surveys, experiments and observational studies, and judging a report

Answer Key - Grade 11 Math Worksheet - Building Confidence

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

1. 1.

   Noah's class assigns 30 bean plants at random: 15 get plant food and 15 get plain water. Then the class measures their growth. Which kind of study is this?

   • An observational study: the class only measured what happened to the plants.
   • A sample survey: it asks a sample questions.
   • An experiment: the class chose, at random, which plants got plant food.

2. Read this first

   Use this

   nobody was assigned.

3. 2.

   Ren measures the ruler-drop catch distances of 25 students who already play a ball sport and 25 who do not. Which kind of study is this?

   • An experiment: two groups of students are compared on their catch distances.
   • An observational study: the students were already in their groups.
   • A sample survey: it asks a sample questions.
4. 3.

   Tala measures the heights of 20 sunflowers already growing in shade and 20 already growing in sun in the school garden. Which kind of study is this?

   • An experiment: two groups of sunflowers are compared on their heights.
   • A sample survey: it asks a sample questions.
   • An observational study: the sunflowers were already in shade or sun.
5. 4.

   800 dots (students); 40 circled by chance, spread all over the plot. Bo picks 40 of the school's 800 students at random to ask about reading. What does the random pick do?

   • It lets the result stand for all 800 students.
   • Nothing: asking the first 40 at the door works as well.
   • It shows what makes students read more.
6. 5.

   400 dots (seventh graders); 50 circled, drawn at random, spread all over the plot. Jun draws 50 names at random from all 400 seventh graders and asks about sleep. Who can the result describe?

   • Only the 50 students asked
   • All 400 seventh graders at the school
   • Every student in the state
7. 6.

   900 dots (students); 60 circled, drawn at random, spread all over the plot. Kira draws 60 names at random from all 900 students and asks about recycling. Who can the result describe?

   • Only the 60 students asked
   • All 900 students at the school
   • Every student in the country
8. 7.

   500 dots (students); the 40 circled all sit in one corner, the front of the lunch line. Luz asks the first 40 of the school's 500 students in the lunch line if lunch should be longer. Who can the result describe?

   • Only those 40 students; the front of the line may not be typical
   • Every student in the state
   • All 500 students at the school
9. 8.

   700 dots (students); the 90 circled are the ones who chose to answer, bunched together. All 700 students could answer Milo's online poll about a later start; 90 chose to answer. Who can the result describe?

   • Only the 90 who chose to answer; they may feel strongly
   • Every student in the country
   • All 700 students at the school
10. 9.

    Noah's report graph starts its axis at 80, not 0. A bar shows 86 votes for a class pet. How many units tall is that bar drawn above the axis start?

    6
11. 10.

    Ren's report graph starts its axis at 30, not 0. A bar shows 37 books returned late. How many units tall is that bar drawn above the axis start?

    7