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ajjones
10-30-2005, 05:51 PM
I have a project due and I am using excel for the first time to compute data analyze.

I need to be sure I am on the right track in accessing coefficient of correlation. I have already begun to computer the formula manually because the number I receive from excel I can't understand.

my formula

E (x1 - xbar) (y1 - ybar)[U]
[U]Sx Sy
n-1

I came up with
xbar = 5,141,686
Sx= 856947.6667
ybar=72,398
Sy= 12066.33333

n=6

What I can't figure out is where am I to look for the (x1) (y1)?????

is this like the r-1 thing? x1= -5,141686....

Signed very confused.

JohnM
10-30-2005, 06:08 PM
Are you given any individual points (i.e., x1, y1, x2, y2, etc.) or just the summary statistics?

Any other summary statistics given? Such as summation of xy?

ajjones
10-30-2005, 06:24 PM
Yes,

I am supply the correlation between retail online sales and total retail sales. Using calculation of the correlation between online and total retail sales to interpret the results. Once I have the formula completed, I am trying to get enough understanding to be able give two examples of correlation which are evaluated in a business environment and discuss the decision made by evaluating the correlation.

I wasn't given any more detail then this plus the ecommerce report which didn't indicate additional points for x1.

So, what I did was add up sx=online purchases totals/6 for the number of entries and the same for sy=retail sales totals.

Did the same for n=6-1

JohnM
10-30-2005, 06:33 PM
OK. If you're just looking for an understanding of the correlation coefficient r, aka Pearson's Product Moment Correlation, it's the strength of the linear relationship between 2 variables, and can vary between -1 (perfect negative correlation - as x increases, y decreases) and +1 (perfect positive correlation - as x increases, y increases). A coefficient of 0 indicates that there is no relationship.

The coefficient of determination, r^2, tells us the proportion of variance in y that is explained by the variance in x.

A very thorough explanation is in Chapter 3 of Vassar College's online stats textbook:
http://faculty.vassar.edu/lowry/webtext.html

ajjones
10-30-2005, 07:02 PM
Many thanks. :)

Noushkary
11-22-2005, 02:09 PM
I Need Help For A Statist Test For Tomorrow!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

JohnM
11-22-2005, 02:15 PM
If you have a specific question, please post it to one of the forums, and we'll do the best we can to give you guidance, hints, .....

bbs1
01-17-2007, 07:29 PM
hello everyone..i'm on a project right now..i want to learn what is the tool for excel..the tool which shows all graphs or charts,guess phstat or phdstat? but i don't know..if you help me to use or download or show me how to download this add-in or toolbar,i'll be prechiated:)