If you had to order t-shirts for your entire school, what sample would you choose to

help you predict how manyt-shirts of each size to order?

In this lesson you will learn how to identify representative

samples by differentiating between biased and unbiased

methods of sampling.

Let’s ReviewThe population is the entire group

being studied.A sample is part of the population being

surveyed.

A Common MistakeHow tall

are 7th graders?Not all samples will lead to good predictions about an entire population.

Core Lesson

Representative sample

Valid inference

?accurate

prediction based on

data

Core Lesson

Sampling method

Unbiased Biased

Core Lesson

This sample comes from a biased sampling method. It is not representative of the

population.

Core Lesson

This sample comes from an unbiased sampling method.

It is representative of the population.

Core LessonAnother example: Color of leaves in September

a) 100 fallen leaves collected from the groundb) 100 leaves on tree branchesc) 50 fallen leaves and 50 leaves on branchesd) 50 fallen oak leaves and 50 oak leaves on branches

Core Lesson

Representative sample

Valid inference

Unbiased sampling method

In this lesson you have learned how to identify

representative samples by differentiating between

biased and unbiased methods of sampling.

Guided PracticeA market researcher wants to know how 18-25 year old women spend their money. Which group would be a representative sample?a) 18-25 year old women at the mallb) 18-25 men and women commuting to workc) Women of all ages commuting to workd) 18-25 year old women commuting to work

Extension Activities

In a complete paragraph, describe why the following sampling method is biased, and suggest an unbiased method.

You want to know your town’s favorite fast-food restaurant. You randomly ask 30 people their preference as they leave one of the fast-food restaurants in town.

Extension ActivitiesChoose a population and something you would like to learn about it. Identify examples of biased sampling methods and unbiased sampling methods.

1. Population: 2. Desired information:3. Examples of biased sampling methods:4. Examples of unbiased sampling methods:

Quick Quiz1. An ice-cream company wants to find out if its ice cream is the favorite in the state. Which group would be a representative sample?a) Customers who visit their storeb) Employees of ice cream stores in the statec) People at the state faird) Adults entering a gym in the capital city

Quick Quiz2. Which is an unbiased sampling method for predicting the type of payment most frequently used at a grocery store?Record the type of payment used by…a) Students at the local high schoolb) Every 10th customer entering the storec) Every 10th customer in the cash-only lined) Visa card holders

Lesson Slides RubricUse this rubric to ensure your

lesson plan is great!

Math Rubric  Criteria for Success Things to avoid

Storyline or Arc of the Lesson

There is a clear arc to the lesson.  One slide leads naturally to the next so that there is a flow and a building of meaning

All the components of the lesson are there but they seem disconnected, as if the author wrote each without thinking about how they fit into the whole. 

Hook Slide

The teacher poses a simple question that illicits the response, “yeah, I do wonder how that works…”  

The question is short A relevant example is included when it is short and 

further pulls the learner in  The question mirrors what the student will learn, then 

need to do later in the guided practice

The question seems formulaic, inauthentic, or overly “school-ish” (message: you have to learn this because you’re in school rather than, this is genuinely interesting)

The hook is overly-complicated and potentially confusing The question does not parallel the guided practice questions

Objective Slide

The objective follows the form (you will learn X by doing Y)

Is concise and follows the form provided in the examples

Does not follow the form Is overly vague in describing either the X or the Y Is too long Is written for teachers but not students

Let’s Review

Reminds the student of how this lesson fits with other lessons (the lesson, however, should still be able to stand on its own)

Reminds the student of important vocabulary Is as concise as possible Uses visuals whenever possible

Is either too detailed or not detailed enough in connecting the lesson to other lessons

Leaves out important touch points Makes the lesson overly dependent on the other lessons 

(student will be confused or feel like they’ve made a mistake, if they watch this lesson alone)

Common Mistake Points out a common mistake that students make  Concisely explains the thought process that leads to that 

mistake

Isn’t actually a mistake students make (too simple) Is confusing or vague

Modeling a Way of Looking at It

Clearly models a way to look at the standard Uses visuals as often as possible to show how the way of 

looking works Is in “think aloud” format.  The teacher is opening up 

his/her thought process to the student Takes advantage of every opportunity to explain why the 

math works the way it works Engages the learner by asking questions along the way to 

build suspense Uses an an example to show the way in action Explains how this way of looking at it shows why the 

common mistake (see above) is a mistake

Focuses on the algorhythm (or trick) instead of on showing a way of looking at the math

Fails to use visuals to show a way Fails to explain his/her thinking along the way.  The teacher 

effortlessly runs through the steps as if it’s all obvious and easy Does not ask any questions along the way to pull the learner in Misses opportunities to explain the why behind the math Fails to explain why this way of looking at the math addresses 

the common mistake

Objective Review

Reviews the objective in a way which conveys, “we’ve come full cicle and now you see this objective with new eyes.”

Serves as a “let’s pull this all together” moment that helps organize the lesson in the learner’s mind

Creates abrupt feeling between the lesson and the reviewing (subtext: “we’re done with this lesson, let’s quickly bring it to a close.”)

Guided Practice Is at the same difficulty level modeled in the lesson  Is connected to the initial hook question

Seem unrelated to the hook question Is at a different difficulty level than that modeled in the lesson

Extension Activity Suggestions

Includes a suggestion for a struggling student who needs more opportunities for practice

Includes a suggestion for students who seem to get it but need more practice

Includes a suggestion for students who get it and are ready to be challenged further

Suggestions should clearly build from the approach in the core lesson

Does not include differentiation Does not thoughtfully connect or flow from the lesson Does not clearly build from the approach in the core lesson Does not give a range of activities

Aesthetics

The slides use the correct colors (blue, green, red) in the correct sequence.

The slides use the correct fonts The slides use handwriting and the handwriting appears 

as written in the right places The slides only use the headers/titles provided  The slides use the provided visuals or include visuals 

created by the author or LearnZillion The slides use animation, highlighting, and circling to 

scaffold the learning, keeping the eye focused on what the teacher is introducing/explaining

The slides clean and uncluttered.  The visuals and text do not exceed the maximum amount (see tutorial for example of maximum)

The slides use other colors or vary the order of the colors The slides add new headers/titles that aren’t part of the 

template The slides use clip art The slides are cluttered Animation is distracting and feels more like sizzle than part of 

the steak

Graphic and Image TemplatesCopy and Paste items from these slides to

make your presentation look great!

You can copy and paste these items into any slide

Green text box that appears letter by letterGreen text box that fades inBlue text box that appears letter by letterBlue text box that fades inRed text box that appears letter by letterRed text box that fades in

You can copy and paste these items into any slide—make sure you copy both the bubble and

the text! Do I feel strongly about it?

Do I have a lot to say?

Do I feel strongly about

it?

Do I have a lot to say? Do I have a lot to

say?

You can copy and paste these items into any slide. You can resize them as

needed! Use black text when you write in me please! Also, keep my text left-justified rather than centered!

Use black text when you write in me please! Also, keep the text left-justified rather than centered!

All arrows can be recolored by changing the “shape fill.” You can also resize them or rotate

them!

[Write first step here…]1

2 [Write second step here…]

3 [Write third step here…]

You can use these when discussing main ideas or steps in a process…

You can resize any of these boxes and use them to highlight text or ideas.

Let’s ReviewA Common Mistake

Guided Practice

Quick Quiz

Extension Activities

Core Lesson