Help with 5 Questions on Correlation Coefficients?

Question

anonymous · Answer

attachment

anonymous · Answer

@Data_LG2 @e.mccormick @TheSmartOne @jim_thompson5910

e.mccormick · Answer

On #1, draw a line mentally that passes down the center of the points.  Would the line have a positive or negative slope?

anonymous · Answer

Negative. @e.mccormick

e.mccormick · Answer

OK, so C and D are eliminated.  Then you just need to see if -.8 or -.25 make more sense.

e.mccormick · Answer

The firs point is (1,8)  The next points, well, are between 2 and 3... so not as clear where they would be.  But, -.25 means that for ever 1 you go over, you lose .25.  -.8 means that for every 1 you go over you lose .8.  

Let me show you with -2 as an example. 

Say I satred with x=1, y=10 and had -2.  Then my next predicted points would be (2,8), (3,6), (4,4) and so on with the x going up one and the y going down two.

For yours, which makes more sense, -.25 or -.8?

anonymous · Answer

-.8?

e.mccormick · Answer

yep!  Cause it is almost a 45 degree down.  That would be -1.

e.mccormick · Answer

OK.  So, for #2, it is the same basic process.  Is it postitive or negative and then how fast does it go up/down.

anonymous · Answer

Positive and .4?

e.mccormick · Answer

Yah.  .95 would go up too fast.

e.mccormick · Answer

or... hmmm...  wait a sec....

e.mccormick · Answer

yah....  it is just a little deceptive on that one but .4 looks best.

anonymous · Answer

Okay. :) What about #3?

anonymous · Answer

@e.mccormick

e.mccormick · Answer

+1 Strongest positive
0 No relation
-1 Strongest negative

So, given those, what is r.044?

anonymous · Answer

Moderate Positive?

e.mccormick · Answer

Yep.

e.mccormick · Answer

On 4, yah, you already knew that...

e.mccormick · Answer

And 5 is a bunch of work.

anonymous · Answer

@e.mccormick Can you help with 5 though.

e.mccormick · Answer

Well, do you know the formulas needed?

anonymous · Answer

No.

e.mccormick · Answer

http://statistics.about.com/od/Descriptive-Statistics/a/How-To-Calculate-The-Correlation-Coefficient.htm

e.mccormick · Answer

It is not hard work... just a lot of it.

anonymous · Answer

So you can't explain it to me?@e.mccormick

e.mccormick · Answer

Well, which of those steps do you know how to do?  Can you find the standard deviation?

anonymous · Answer

No, i don't even know where to start...

anonymous · Answer

@girlover @iambatman @bibby @dan815 @dtan5457