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7th grade · Math · Unit 16 of 17

Samples & Populations

Random samples and estimates

What your child practices

Telling a sample from a population, choosing a fair random sample, and using sample results to estimate for a whole population.

California Content Standards learning standard: 7.SP.1; 7.SP.2 · using random samples to draw inferences about a population

How we explain it

Children can open this short lesson before they practice.

  1. The population is the whole group. A sample is part of it.
  2. A random sample gives everyone an equal chance to be picked.
  3. Use the sample's fraction to estimate for the population.

Example: In a random sample of 50 students, 10 bike to school. About how many of 400 students bike? 10/50 = 1/5. 1/5 of 400 = 80. Answer: About 80

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    One random sample has 30 people and another has 300. Which estimate of the population is likely to be closer?

    • The sample of 30
    • The sample of 300
    • They will always be exactly the same

  2. Question 2

    A school asks 60 of its 900 students about field trips. What is the population?

    • the 60 students asked
    • the teachers
    • all 900 students
    • the field trips

  3. Question 3

    You want to know how voters in a city feel about a new park. Which sample is most likely to represent the population?

    • 200 voters picked at random from the city's voter list
    • the first 200 people who email the city
    • 200 people who live next to the park
    • 200 people at a park opening

  4. Question 4

    In a random sample of 50 students, 12 walk to school. About how many of the 400 students at the school walk to school?

    • 304
    • 120
    • 146
    • 96

  5. Question 5

    A school asks 60 of its 900 students about field trips. What is the population?

    • the teachers
    • all 900 students
    • the 60 students asked
    • the field trips

  6. Question 6

    You want to know how voters in a city feel about a new park. Which sample is most likely to represent the population?

    • the first 200 people who email the city
    • 200 voters picked at random from the city's voter list
    • 200 people who live next to the park
    • 200 people at a park opening

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