# Coefficient of correlation

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

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

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 . In any case, http://encyclopedia.thefreedictionary.com/Coefficient+of+determination might help.
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?