Understanding Bar Graphs Unit of Study: Data Global Concept Guide: 3 of 3

Content Development Classroom discussion should continue to foster connections between line plots, tally charts, picture graphs, and bar graphs. Interpreting a bar graph requires students to comprehend the graph is a model of data. Go Math! identifies several skills students must apply to interpret a bar graph.  The title and topic of the data  Labels for categories and the scale  The individual categories of data  The amounts the bars represent Teachers should be cautious to not focus on the techniques of graph construction to the exclusion of data comprehension. Students should be able to write statements which include numerical data about a bar graph and be involved in discussions about why data was collected and how it is was organized for the “reader”.

Day 1  Connections between picture graphs and bar graphs can be supported by using countable, rectangular objects as picture symbols and transitioning to the bars, (See TE 481)  The focus of Day 1 is on interpreting the data represented by a bar graph. Students should understand a bar graph is another way to model mathematics. Models presented to students should include horizontal and vertical bar graphs.  Presenting students with a bar graph lacking a title, category labels, and scale is a suggestion for emphasizing the value of these components for students. Generalizations can be made about the graph, yet students will struggle to find true meaning in the graph. As the components are added, students will be able to construct meaning to the bar graph and generalize the value of these components for the reader.

Day 2  Day 2 engages students in construction of a bar graph. A title, category labels and a unit scale are expectations. Students may use prepared data and complete graphs as per lesson Student products should be monitored for accuracy of data representation as per the unit scale.  Classroom discussion should include comparing information shown on a bar graph and solving problems related to the data. The “On Your Own” and “Problem Solving” components from are suggestions for comprehension combined with accuracy in completing a bar graph.  Some students may be ready to pose their own survey question, gather the data, and represent the data on a bar graph.

Day 3  Day 3 combines the accuracy of bar graph construction with analyzing data. The goal is for students to understand graphs convey factual information and provide opportunities to make inferences based upon data. Teach & Talk from 10.6 is an example. Teachers may prefer to use data collected from class survey questions or science investigations.  Students should be encouraged to write statements about graphs using numerical data and be able to make generalizations about data trends and implications. Join together, separate, and compare problem solving structures using the data within the bar graph is appropriate.

Sample Survey Questions for Collecting Data  How many letters in your last name ?  Which of these is your favorite color?  Which coins in our scoop? (scoop a handful of coins and sort)  Which of these fruits is preferred at lunch?  Which Dr. Seuss book is your favorite?  Which type of seed should we plant?

Enrich/Reteach/Intervention Constructing a glyph graph is a strategy for encouraging students to think flexibly about data. Glyphs are a pictorial form of data collection which may be organized and analyzed for different attributes. Students may construct bar graphs to compare and contrast data about a particular attribute as enrichment. Students who need support may benefit from connecting snap cubes together to represent data quantities for each category. Students would record the titles and labels on index cards or sentence strips and use the snap cubes as a concrete example of the bar graph. See TE page 477A. Proceed by having students construct a representation of the model on prepared grid paper.

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