Data - Lesson 4: Exploring Two Columns

Overview

Students will practice making conclusions from charts and learn to use Quorum Studio for two different kinds of charts, a cross tab, and a scatterplot. Students will practice reading each type of chart before learning to make them. Students will track their work using a provided activity guide. The lesson concludes with a review of key takeaways.

Goals

Students will be able to:

  • Create a crosstab and scatter charts in Quorum Studio
  • Draw conclusions by reading crosstab and scatter charts
  • Explain the reasons that someone would create either a crosstab and scatter chart in order to explore two columns of data

Purpose

This lesson introduces students to two new ways of make visualizations. The crosstab and scatter chart are new in that they allow students to see patterns across multiple variables, noticing how one might seem to change (or correlate) with another. This is good preparation for their unit project in which they'll need to make and interpret a data visualization of their own.

Goals

Preparation

Review how to make crosstab and scatter charts in Quorum Studio

Activity (30 mins)

Reading Crosstab Charts

Discuss: How many 'Herding' breeds live a maximum of 12 years? What is the most common maximum life span for 'Working' breeds? Which breed group lives the shortest? Which breed group lives the longest? How do you know? How confident are you in your answers?

Do This: Run a short discussion and help students read the chart together. They will hopefully note the following:

  • 4 herding breeds live a maximum of 12 years
  • The most common maximum lifespan of working breeds is 12 years
  • Toy breeds seem to live the longest
  • Working breeds seem to be the shortest
  • Students can see the spread of life expectancies for different breeds but it's not cut and dry.
Teaching Tip

Understanding Crosstab: Understanding Crosstab: Give students some time to think and discuss why a crosstab chart might be a good choice for finding patterns like the ones indicated on this slide. Further reinforce the fact that if either column has too many values you may end up with an enormous chart.

Display: Open the file LifeVsBreed.csv, which is in the folder Lesson4_App1 in Excel or another spreadsheet program. Examine this to introduce cross tab charts and how they work.

Making Crosstab Charts

Distribute: Give students access to Exploring Two Columns - Activity Guide

Teaching Tip

Fill Out the Activity Guide Digitally: We can access data in many different ways. Code.org's Data Visualizer is one, but using Quorum to output a Crosstab to a file, and opening it in Microsoft Excel, is another.

Do This: Have students go to the Lesson4_App1 in the Unit9 folder of the CSP Widgets and use both the 'Words' and the 'Favorite Classes' data sets to complete page 1 of the Activity Guide.

Discuss: Optionally have students share their progress and discuss the conclusions they reached on side one of the activity guide.

Reading Scatter Charts

Have students go to the Lesson4_App2 in the Unit9 folder of the CSP Widgets. This app generates an accessible scatter plot related to when states were admitted to the United States and their land mass in square miles.

Do This: Is there a pattern? How can you tell?

Discuss: Have students share whether they think there's pattern between the order in which states were admitted and their size.

Discussion Goal

Goal: Students will hopefully notice later states are relatively larger than earlier added ones. The trend does not necessarily reflect any causation, but there is a slight uptick in state size as more are added.

Display: Have students run the code in Lesson4_App2 and examine the chart produced.

Making Scatter Charts

Do This: Have students fill in page 2 of their activity guides practicing making scatter charts.

Discuss: Have students share our their responses and talk through their conclusions.

Wrap up (10 Minutes)

The key takeaway is that the Data Analysis process has four key steps. First, we collect or choose the data. Second, we clean and filter it. Third, we try to find patterns in the data, through creating charts or using statistics. Finally, we try to find new information.

For charts, we decide how to create them via the information we know about the data and by thinking about what we want to learn. For example, if we have 1 column of numerical data, we might use a bar chart or a histogram to view it. If we have two columns, cross tabs can be useful if we have strings and few items, while scatterplots can be useful if we have a lot of numerical data.

  • Students know a lot of different ways to find patterns in data
  • Review the chart showing how the can decide the type of chart to create
  • Have students record key takeaways in their journal

Assessment: Check for Understanding

For Students

Open a word doc or google doc and copy/paste the following question.

Question

How are the questions you can investigate with scatter or crosstab charts different from the ones you can investigate with bar charts or histograms?

Standards Alignment

  • CSTA K-12 Computer Science Standards (2017) 3A-DA-11, 3B-DA-05, 3B-DA-06
  • CSP2021: DAT-2.E.4, DAT-2.E.5

Next Tutorial

In the next tutorial, we will discuss Code.org Unit 9, which describes explore innovations in everyday life.