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7th grade · Math · Unit 14 of 22

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.

Texas Essential Knowledge and Skills (TEKS) teks student expectation: 7.6(F); 7.12(B) · using a random sample to make 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

Samples & Populations in Texas

In the Texas Essential Knowledge and Skills (TEKS), this is unit 14 of 22 in 7th grade Math, after Dependent Events and before Circle Graphs.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Texas Education Agency (TEA)

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 20 people and another has 300. Which estimate of the population is likely to be closer?

    • The sample of 20
    • They will always be exactly the same
    • The sample of 300

  2. Question 2

    You want to know the favorite sport of students at a school. Which sample is most likely to represent the population?

    • 50 friends of the survey writer
    • 50 students at a basketball game
    • the 50 students on the soccer team
    • 50 students chosen by a random draw of student numbers

  3. Question 3

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

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

  4. Question 4

    In a random sample of 50 students, 5 play an instrument. About how many of the 300 students at the school play an instrument?

    • 50
    • 80
    • 270
    • 30

  5. Question 5

    In a random sample of 50 students, 18 ride the bus. About how many of the 450 students at the school ride the bus?

    • 162
    • 288
    • 212
    • 180

  6. Question 6

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

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

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