Why can some people roll their tongues but others can’t?

There is investigation focuses on students examining an association between two categorical variables. Specifi cally, they will investigate whether there is an association between gender and whether a person can roll their tongue. As part of this investigation, students will collect, organize, and analyze data in a two-way table; construct and analyze segmented bar graphs; and calculate the percentages of boys and girls who can roll their tongue. Th is investigation is based on an activity in Probability Th rough Data, a module in the Data-Driven Mathematics series (1999).

Th is investigation follows the four components of statistical problem solving put forth in the Guidelines for Assessment and Instruction in Statistics Education (GAISE) Report. Th e four components are formulate a statistical question that can be answered with data, design and implement a plan to collect appropriate data, analyze the collected data by graphical and numerical methods, and interpret the results of the analysis in the context of the original question. Th is is a GAISE Level B activity.

Students will be able to do the following after completing this investigation:
• Organize data collected into a two-way table
• Analyze data in a two-way table

Common Core State Standards for Mathematical Practice

1. Make sense of problems and persevere in solving them.
2. Reason abstractly and quantitatively.
3. Construct viable arguments and critique the reasoning of others.
4. Model with mathematics.