Sampling in a Fair Way
5 min
Teacher Prep
Setup
Narrative
The purpose of this Warm-up is for students to begin to see that different samples are more or less representative of the population from which they are drawn. Students are asked to look at a dot plot and reason about the context of the sample by matching it to their expectations about what the population should be.
Launch
Arrange students in groups of 2. Give students 1 minute of quiet think time, then 1 minute to discuss the things they notice with their partner. Follow with a whole-class discussion.
Student Task
A survey was taken at a movie theater to estimate the average age of moviegoers.
Here is a dot plot showing the ages of the first 20 people surveyed.
- What questions do you have about the data from survey?
- What assumptions would you make based on these results?
Sample Response
Sample responses:
-
- Why is everyone so young?
- Why is there a 4 year old at the theater?
- Why were parents not surveyed?
-
- There must be at least one G-rated movie playing at the theater.
- Maybe the survey was taken during a child’s birthday party.
- There are a lot of young people at this theater.
Activity Synthesis (Teacher Notes)
The purpose of the discussion is for students to express their expectations for who would be at the movie theater and whether this group represents that expectation.
Ask several students to report any questions or assumptions they have about the information provided. If possible, display the dot plot so that students can refer to it while giving their answers.
Standards
- 7.SP.1·Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.
- 7.SP.A.1·Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.
10 min
10 min
10 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Sampling in a Fair Way
5 min
Teacher Prep
Setup
Narrative
The purpose of this Warm-up is for students to begin to see that different samples are more or less representative of the population from which they are drawn. Students are asked to look at a dot plot and reason about the context of the sample by matching it to their expectations about what the population should be.
Launch
Arrange students in groups of 2. Give students 1 minute of quiet think time, then 1 minute to discuss the things they notice with their partner. Follow with a whole-class discussion.
Student Task
A survey was taken at a movie theater to estimate the average age of moviegoers.
Here is a dot plot showing the ages of the first 20 people surveyed.
- What questions do you have about the data from survey?
- What assumptions would you make based on these results?
Sample Response
Sample responses:
-
- Why is everyone so young?
- Why is there a 4 year old at the theater?
- Why were parents not surveyed?
-
- There must be at least one G-rated movie playing at the theater.
- Maybe the survey was taken during a child’s birthday party.
- There are a lot of young people at this theater.
Activity Synthesis (Teacher Notes)
The purpose of the discussion is for students to express their expectations for who would be at the movie theater and whether this group represents that expectation.
Ask several students to report any questions or assumptions they have about the information provided. If possible, display the dot plot so that students can refer to it while giving their answers.
Standards
- 7.SP.1·Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.
- 7.SP.A.1·Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.