Free Statistics Help Book
An Interactive Multimedia introductory-level statistics book.
The book features interactive demos, simulations and case studies.
Chapter
Section
Summarizing Distributions :  

Variability



Prerequisite
None


1. Measures of Variability
2. Variability Demo
3. Estimating Variance Simulation


Variability refers to how much the numbers in a distribution differ from each other. The most common measures are presented in “Measures of Variability.” The “variability demo” allows you to change the standard deviation of a distribution and view a graph of the changed distribution.


One of the more counter-intuitive facts in introductory statistics is that the formula for variance when computed in a population is biased when applied in a sample. The “Estimating Variance Simulation” shows concretely why this is the case.
Copyright 2011