Question

Describe an association between two variables. Give a confounding variable that may help to account for this association. People with shorter hair tend to be taller.

Short answer

The observed association is that people with shorter hair tend to be taller - indicating a negative association between hair length and height. A potential confounding variable in this case could be 'gender' - as generally, men tend to have shorter hair and are typically taller.

Step-by-step solution

Understanding the Variables

Analyze the given statement: 'People with shorter hair tend to be taller.' Here, two variables are given - hair length and height. These are the two variables to be analyzed.

Describe the Association

Based on the provided statement, the observed association could be described as: as hair length decreases (or the shorter the hair), the height tends to increase (or people tend to be taller). This indicates a negative relationship or association between the two variables - hair length and height.

Give a Confounding Variable

A confounding variable is an external factor that might influence the outcome of the study, or 'confound' the results, hence the name. In this case, a potential confounding variable could be 'gender'. In many societies, men, who tend to be taller on average, also tend to have shorter hair. Therefore, the association that people with shorter hair tend to be taller might actually be influenced by this confounding variable - gender.