[CFA Level I] 21, Mean Median and Dispersion in Return Data

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 the median provides an outlier-robust measure of central tendency compared to the arithmetic mean. • Why sample variance uses n minus one in the denominator to eliminate estimation bias. • How Bessel's correction adjusts sample variance for degrees of freedom lost when estimating the sample mean. • Why standard deviation restores variance from squared units back to original percentage return units. • Common calculation traps involving sample versus population dispersion on the CFA Level I exam. This independent study supplement is designed for self-paced exam prep. Practice CFA Level I questions and tools: https://open-exam-prep.com/practice/cfa-level1 or subscribe on YouTube: https://www.youtube.com/@Open-exam-prep . Sources checked: October 12, 2026 • https://www.cfainstitute.org/programs/cfa-program/candidate-resources/level-i-exam • https://www.cfainstitute.org/sites/default/files/2027levelitopicoutline_online.pdf