# Biased versus Unbiased Samples - What does your sample represent?

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## Objective

Students will be able to distinguish between biased and unbiased samples, and check the validity of conclusions.

#### Big Idea

Want to know how many of your friends you can predict to be at the next dance? Make sure you use an unbiased sample to make your prediction!

## Launch

10 minutes

Opener:  As students enter the room, they will immediately begin working on the opener.  The opener is a mixture of previously learned questions, and students should work individually, and then as table groups to discuss the methods for solving the questions.  After approximately 5 minutes, I will call on students to go to the board and solve the opener questions.  As with all openers, I will take volunteers to go to the board – the volunteer is expected to explain their reasoning, and other students are expected to follow along with the work and ask questions/make suggestions as necessary.  By having a student explain their reasoning while others listen and provide feedback, mathematical practice 3 – construct viable arguments and critique the reasoning of others – becomes a natural part of class.

Learning Target: After completion of the opener, I will address the day’s learning targets to the students.  In today’s lesson, the intended target is, “I can determine whether a sample is biased or unbiased, and therefore whether conclusions made are valid.” Students will jot the learning targets down in their agendas (our version of a student planner, there is a place to write the learning target for every day).

40 minutes

## Summarize + Homework

10 minutes

Exit Ticket: To summarize this lesson, and to really get an idea of whether the students can distinguish between a biased and unbiased sample, I am going to ask that on the back side of their opener, they give me an example of each, and that on their way out of the classroom, they place their paper on the opener table.  Creating his or her own example will demonstrate a student’s true understanding.  Students that are unable to write their own example of each type of sample will be pulled in for extra help during morning reading time, or during the opener tomorrow.

Homework: I will pass out the homework, and students will take the last couple minutes of class to look over the homework and ask any questions that they may have regarding the assignment. Philosophy on Homework