Coefficient of correlation

[adeel]

In a sample of 21 observations obtained it was found that sales and price have an inverse relationship and coefficient of determination is 106% as much as the adjusted coefficient of determination. It is also known that the variance of sales around mean is 640. What is the coefficient of correlation?

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Im not sure how all the information fits together. I know coefficient of determination is SSR/SST, but i dont have any of that information

[adeel]

im not really sure what variance of sales around mean, means...help?

[adeel]

is sum of squares total the same as the variance around the mean?

[bomba923]

is sum of squares total the same as the variance around the mean?

Variance is the coefficient of determination, which is the square of the coefficient of correlation. Adjusted, I think, means calculated from a linear regression with outliers eliminated. However, I may be totally wrong :redface:. In any case, http://encyclopedia.thefreedictionary.com/Coefficient+of+determination might help.

[EnumaElish]

Another way coef of corr between X and Y is defined is Corr(X,Y) = Cov(X,Y)/(\sigma_X\sigma_Y) where "sigma" is the standard dev. of the subscripted variable. Maybe it is this formula that the problem is asking about?