Discussion topic: Variance ~ help me understand it! by due date (to do so, just click the “reply” button below). In your post please include the following:

1. What is the one thing you need help on.

Please reply to at least one other student’s post. In your reply, please do one of the following: Help Each Other!!!

1. Offer your help, if you understand it.
2. Ask for help of clarification from you classmate.
3. Ask: did I calculate this right

_________________________________ Respond to

Katherine-

My question regarding z-scores piggy-backs on my response to Anna’s post above regarding why +/- 2.00 is considered the extreme boundary. When referencing the Unit Normal Table, I see that z-scores are listed from 0.00 to 4.00. Yet, I’m halfway through Chapter 7 and haven’t seen a distribution graph with a z-scores above or below 2. Is it a low probability and very rare that z-scores ever go beyond -2/+2? This is jumping ahead, but does that “arbitrary” boundary relate to the concept of sample means piling up in the center of the distribution (chapter 7)?