Final answer:
Psychological knowledge, especially in the realm of health psychology, plays a significant role in improving the quality of life by influencing health-related behaviors and treatments for mental illness using scientific methods.
Step-by-step explanation:
Treatments for mental illness, the ability to change unhealthy behaviors like smoking, adopting healthy habits such as exercise, and developing positive parenting practices all demonstrate that psychological knowledge can be used to help improve the quality of life. Psychology, as the scientific study of mind and behavior, uses the scientific method to understand and shape human behavior in positive ways, which contrasts other methods such as intuition and personal experience. Health psychology, a subfield of psychology, specifically examines how psychological factors affect health and develops interventions to promote healthy behavior, highlight the practical applications of psychological research in improving daily living.