MP3: Construct viable arguments and critique the reasoning of others.

The candy bar survey task asks students to read the survey result data, represent it using charts or graphs, construct an conclusion based on the data, and critique the reasoning of another person. Mathematical practice standard 3 states, "distinguish correct logic or reasoning from that which is flawed, and - if there is a flaw in the argument - explain what it is." Part 2 (a) of the task requires students to identify 2 reasons that an argument is incorrect. The standard also states that students "reason inductively about data, making plausible arguments that take into account the context from which the data arose." Part 2 (b) of the task asks students to draw a conclusion that is supported by the data.

Students may struggle with the portion of this task in which they must give 2 reasons why Chris' argument is wrong. On the surface, the claims in Chris' statement are correct and would require an understanding of measures of center and the problem that simply comparing total numbers would pose.

This task might be made more engaging if students were given the opportunity to choose a question about their peers, collect their own data, and draw conclusions about the males vs females or the class as a whole. A teacher would want to monitor the survey questions and guide students away from questions that may be uncomfortable for their peers to answer.

To help create a lower floor for this task, I would scaffold students' understanding of how best represent data, possibly guiding them toward exploring the measures of center of the data. I might also break down Chris' argument into pieces and have students discuss and share out their thoughts on the validity of each piece. I would raise the ceiling on a task like this by having students collect their own data using a question of their choosing. I would also challenge students to represent their data using a graph type they have not used yet for the task. Each group would present their findings and conclusions about the data and the class could evaluate the validity of the conclusions.