# Descriptive Statistics

## Objective

Create scatterplots and identify function shapes in scatterplots.

## Common Core Standards

### Core Standards

?

• HSS-ID.B.6 — Represent data on two quantitative variables on a scatter plot, and describe how the variables are related.

?

• 8.SP.A.1

## Criteria for Success

?

1. Understand that scatterplots compare the relationship between two quantitative variables.
2. Create scatterplots by identifying appropriate variables (and assignment of assumed dependent/independent) and appropriate scales.
3. Make observations about the clustering, outliers, and general shape of the collection of points on the scatterplot.
4. Identify the most appropriate function shape for the collection of points in a scatterplot.
5. Relate the shape of the graph and clustering to a positive association, negative association, or no association.
6. Make conjectures about the relationship between the two variables based on the visual appearance of the strength of association.
7. Distinguish between correlation and causation, describing that a strong association does not indicate that the independent variable causes the dependent variable.

## Anchor Problems

?

### Problem 1

Each point in the scatterplot below shows one individual’s height, in inches, and weight, in pounds.

The range of the data presented is ${120 \leq y \leq 190}$.
The domain of the data presented is ${63 \leq x \leq 72}$.

Label the axes with the appropriate variables and units, and mark quantities on the axes in an appropriate scale.

### Problem 2

Match the scatterplot with the description. Write a scenario for the scatterplot that does not have a description.

#### References

New Visions for Public Schools Connecting Representations - Connecting Situations to Scatter Plots

Connecting Representations - Connecting Situations to Scatter Plots is made available by New Visions for Public Schools under the CC BY-NC-SA 4.0 license. © 2017 New Visions for Public Schools. Accessed https://docs.google.com/document/d/1UtWBDN15MiFByupfQDic2AjRXoRKatFVUwDRfsbZgug/edit.

## Problem Set

?

The following resources include problems and activities aligned to the objective of the lesson that can be used to create your own problem set.

• This is a three-act task that you should consider including during the lesson: Tap into Teen Minds, “Candle’s Burning”
• Incorporate problems with the identification of variables, scale, the shape of the function, and prediction of when the candle might burn out.
• Make sure to have students identifying variables so they are prepared to talk about what their comparisons mean in later lessons.

?

You plan to buy a bike helmet. Based on data presented in this lesson, will buying the most expensive bike helmet give you a helmet with the highest quality rating? Explain your answer.