# Stat... bzuh?

Okay. I have a Stat 101 test tomorrow. Between having talked to the TA yesterday, and the roommate today, and the boyfriend a few days ago, I understand pretty much everything that the test is going to be over.
Almost. I have r issues.

Issue 1. My book lists it as (screen shot from the notes)

Do I multiply the result of the first bit by the result of the second bit? {edit}okay, I totally blanked on the big parentheses. they weren't in my other notes. and in the second bit, what order does the top line go in? (Sum of all x-xbar) multiplied by (sum of all y-ybar), or (Sum of all x-xbar) multiplied by y-ybar?

Issue 2. What does r^2 mean? We're supposed to be able to interpret it "in the context of the problem." The best example I can give of what they want is for the slope of the least-squares regression line, which we're supposed to interpret as "For every one unit increase in (explanatory variable), there is on average a/n (increase for positive slope, decrease for negative) of (slope) in (response variable)." So, some sort of fill in the blank statement about what r^2 means. I have "% variation" written next to it on my paper from when he started saying it, then he said it was in the notes online... I'm not seeing it.

So far I've asked the roommate and one two of the geeks in my house(I have to wait for the rest to get back from class). They boggled and said my stat book was on crack. Haven't asked the boyfriend yet, but I know he thinks my book is the least helpful book ever written.
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