3 Graph Literacy Lessons This module contains four lessons that can be taught independently or as a unit. The lessons are intended to help students analyze and explain graphs and are not intended to help students make their own graphs.
Resource Page– Review and background information and sources for the teacher.
Lesson 1 – Using Graphs to Inferring Relationships between Variables Goal: To infer the relationships between variables by analyzing the slope of a graph.
Lesson 2 - Common Mistakes or Intentional Distortions in Graphs Goal: To compare and contrast graphs in order to identify graphs that have errors and have been distorted in order to misrepresent the relationship between variables.
Lesson 3 - Interpreting a Graph and Writing a Narrative Summary Goal: To locate, read and interpret data from a line graph, bar graph or pie chart; identify pattern; deduce relationships and formulate generalizations. To form a logical argument that is supported by the graph or chart and to clearly and concisely express it in their written conclusion.
Background – Graphs are increasingly being used in written communication and oral presentations and writers and speakers expect readers to understand them. Fundamental to comprehending or reading graphs is knowing the different parts of a graph and what they can tell you. In the following lessons we will teach you how to read and explain a line graph, pie chart and bar graph. We will also show you how to identify common mistakes or distortions that are made when graphing that can lead to misunderstanding of the data.
Review and background information and sources for the teacher Parts of a Graph
Each type of graph has characteristics that make it useful in certain situations.
Line graphs are used as a way of communicating the relationship between two variables over time. The vertical axis should be the dependent variable (recorded numerically) and the horizontal axis should be time.
Scatter plots which require a line of best fit between separate points in order to find the correlation between the two variables should not be confused with line graphs. The graphs can look very similar because of the line between points.
Bar graphs are used to compare products, populations or trials in one area of interest. The horizontal axis is a list of constants, and the vertical axis is the dependant variable which is recorded numerically.
Pie charts are best used for comparing the parts to the whole. They parts are often shown as percentages of the whole and should add up to 100%. Multiple pie charts can be used to compare populations to each other.
Sources for Reviewing Types of Graphs and Their Parts and Uses Parts of the bar graph
http://cstl.syr.edu/fipse/tabbar/revbar/revbar.htm Parts of a line graph
http://www.kipbs.org/new_kipbs/fsi/Files/GraphingTips.pdf Understanding pie charts
Lesson 1 - Using Graphs to Infer Relationships between Variables
Goal: To infer the relationships between variables by analyzing the slope of a graph.
Background: In addition to drawing graphs, it is also important that you be able to interpret data that is represented in graph form. The following activity is designed to help you develop the ability to read information shown on a graph.
For each group of students copy and cut apart the following page of graphs and their descriptions.
Have students match the graph to its description.
Show students the key after most of the class is done and then have them draw a series of graphs on the blank page that tell a story. Note the following example.
Identify the graph that matches each of the following stories:
I had just left home when I realized I had forgotten my books so I went back to pick them up.
Lesson 3 - Interpreting a Graph and Writing a Narrative Summary Goal: The student is able to locate, read and interpret data from a line graph, bar graph or pie chart; identify pattern; deduce relationships and formulate generalizations.
The student is able to form a logical argument that is supported by the graph or chart and to clearly and concisely express it in their written conclusion.
Instructions: Review the following graphs and fill in the blanks.
Use the information you have recorded to write a short summary of what is being shown by the graph, and what you think is important to notice about the information.
Remember, all statements must be supported by the data on the graph.
Subject of the graph _______________________________________________________________________
x – axis variable _________________________ y – axis variable and units _________________________
Highest bar _______________________________ Lowest bar _____________________________________
Range of the data ______________________________________ Source of data _______________________
Are there any patterns? ______________________________________________________________________
Summary of the graph ______________________________________________________________________
Student does not understand the concept of data selection.
Data selection is haphazard and inappropriate to the task.
Data selection is almost always appropriate for analysis.
Student consistently selects appropriate and best data for reading and interpretation.
Graph Interpretation and Summary
Supportable patterns and relationships in the data are not identified. Illogical conclusions or generalization are drawn from the data.
There are many errors in reading and interpreting data. Ability to detect patterns and relationships in the data is limited,
Incomplete or incorrect conclusions are drawn from the graph, and a limitation of the data is not noted.
There are occasional and isolated errors may occur in the interpretation of the graph. Awareness of pattern and relationship within the data set is noted but not clearly written. Conclusions are less perceptive and awareness of the limitations of the data is unclear.
The analysis of graph is complete and precise with respect to labeling and scaling axis. Student recognizes patterns and relationships within data and clearly describes them in their writing. Supportable conclusions are drawn while recognizing that there are limitations to the data.
Clarity of Communication
Student did not express their understanding of the data in coherent manner.
Student’s ability to express their understanding of the graph is limited and their written interpretation includes many errors.
Student’s presentation is less focused and organized and their understanding is less clear. Their written interpretation is poorly edited and contains a few errors in writing conventions and/or vocabulary.
Student clearly and fully articulates their understanding of the data, including patterns, relationships and generalizations drawn from the data. Math terms are correctly used and language is clear and concise. Writing conventions are correct in written interpretation.