I need asap

Hello Everyone,

Good job participating in our Week 1 discussions!  Please do your best this week to reply to THIS post rather than creating new messages in response.  The reason for this is that my original post gets buried and other students have a hard time finding my original post which contains the questions.  Please try to just reply to this post instead.  Also, please remember that you need a citation/reference to a credible source, such as our textbook, on at least 4 posts per week.  Here are the discussion starters for Chapter 4:

• 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? 

Looking forward to our discussions on these topics this week!