Synopsis:  Students explore the fifth of five possible explanations for finding an association: bias.  Students critique a hypothetical study testing the hypothesis that heavy backpacks cause back pain and learn how the selection of a sample of subjects for a study can produce an association when no association exists in the overall population.  They continue to learn that causation is only one explanation for finding an association between an exposure and an outcome; that because observational studies are flawed, other explanations must also be considered, including selection bias.

All students will develop problem-solving, decision-making, and inquiry skills, reflected by formulating usable questions and hypotheses, planning experiments, conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.

All students will integrate mathematics as a tool for problem-solving in science, and as a means of expressing and / or modeling scientific theories.

All students will learn and apply health promotion concepts and skills to support a healthy, active lifestyle.

All students will use health-enhancing personal, interpersonal, and life skills to support a healthy, active lifestyle.

All students will use mathematical processes of problem solving, communication, connections, reasoning, representations, and technology to solve problems and communicate mathematical ideas.

All students will speak in clear, concise, organized language that varies in content and form for different audiences and purposes.

All students will listen actively to information from a variety of sources in a variety of situations.

All students will demonstrate critical life skills in order to be functional members of society.