What should Richard do to address the confounding variable of age in his experiment?

In experimental research, addressing confounding variables is essential to ensure that the results are valid and accurately reflect the relationship being studied. By holding the age constant and selecting participants from only one age group, Richard can eliminate the potential influence of age on the outcome of his experiment. This approach allows any observed effects to be attributed more confidently to the independent variable being manipulated, as variation due to age is removed from the equation.

When age is held constant, it helps create a more controlled environment where other variables can be assessed without the interference of age-related differences. This can be particularly important in experiments where age could significantly impact the dependent variable, ensuring that the findings are more reliable and interpretable.

Selecting only one age group means that Richard is not only controlling for age, but he is also simplifying the analysis, making it easier to draw conclusions about the effects of the independent variable. This method ensures that age as a confounding variable does not obscure the results of the study.