• What is variability? What are the three types of variability? Why is variability valuable as a descriptive tool? Explain how to calculate and give an example for each type.
• What is the most frequently used measure of variability? What does this measure represent?
• What is an unbiased estimate and why are unbiased estimates usually "best practice" in statistics?
• How are the standard deviation and the variance the same? How are they different?
• What are the degrees of freedom for sample variance?
• What does the standard deviation measure?