Data Analysis and Interpretation in Psychological Research

Researchers designed a study to investigate the impact of a new cognitive-behavioral intervention on reducing anxiety symptoms among adolescents. They collected data using self-report questionnaires measuring anxiety levels both pre- and post-intervention from a sample of 200 adolescents aged 12-18. The researchers also included a control group of 100 adolescents who did not receive the intervention.

After six weeks, the data revealed that the experimental group showed a significant reduction in anxiety scores compared to their pre-intervention scores, while the control group exhibited minimal change. The researchers reported an effect size of 0.65 for the intervention's impact.

Based on the data described, address the following:

1. Identify one potential limitation of the study's design and explain how it could affect the interpretation of the results.
2. Discuss how an appropriate statistical analysis could validate the researchers' conclusions about the effectiveness of the intervention.
3. Describe how the researchers could improve the study design to enhance data reliability in future research.