This Concept introduces students to the some of the measures of spread commonly used, such as range, standard deviation and variance.
An experiment and explanation are offered as to why n-1 rather than n is used to calculate standard deviation.
The answers to questions about standard deviation. Answers two questions: why a standard deviation takes the square root of the average of the sum of the squared differences between X and X mean, and why n vs n-1 is used in calculations.
A Q&A website answers the question of why n-1 instead of n is used in calculating standard deviation.