Question

A study showed the same level of T cell production in senior citizens who are amateur cyclists as in young adults, but a significantly lower level of T cell production in senior citizens who do not exercise regularly. Is it appropriate to infer that exercise stimulates T cell production? Explain. (Source: University of Birmingham)

Accepted Answer

Step 1: Begin by identifying the type of study described in the problem. This appears to be an observational study, as it compares T cell production levels across different groups without actively manipulating variables. Step 2: Understand the key groups being compared: senior citizens who are amateur cyclists, senior citizens who do not exercise regularly, and young adults. Note that the study observes differences in T cell production levels among these groups. Step 3: Consider the concept of causation versus correlation. While the study shows an association between exercise and higher T cell production in senior citizens, it does not establish causation because other factors (e.g., diet, genetics, or overall health) could influence T cell production. Step 4: Reflect on the limitations of observational studies. Without a controlled experiment (e.g., randomly assigning participants to exercise or non-exercise groups), it is not possible to definitively infer that exercise stimulates T cell production. Step 5: Conclude that while the study provides evidence of a correlation between exercise and T cell production, further experimental research would be needed to establish causation and confirm that exercise directly stimulates T cell production.

Verified video answer for a similar problem:

Key Concepts

Causation vs. Correlation

Control Groups

Statistical Significance