This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams. In this episode you will learn: - How arithmetic mean and expected return measure central tendencies in investment analysis. - Why standard deviation represents total risk, incorporating both systematic and unsystematic volatility. - The meaning of correlation coefficients ranging from minus one point zero to plus one point zero. - How combining assets with negative correlation provides maximum portfolio risk reduction. - Key exam traps regarding statistical risk measures and portfolio diversification principles. This episode provides independent study materials for Series 66 test preparation. Practice questions and video tutorials are available at https://open-exam-prep.com/practice/series66 and https://www.youtube.com/@Open-exam-prep . Sources checked: September 14, 2026 https://www.nasaa.org/wp-content/uploads/2023/02/Series-66-Outline-June-2023.pdf https://www.nasaa.org/exams/general-exam-information/series-66-exam-content-outline/