In the first case, there is a strong upward-sloping relationship between X and Y; in the second case, no apparent relationship; in the third case, a strong downward-sloping relationship. Note the ...

Correlation coefficients range from -1 to +1, indicating the strength of relationships between variables. Investors use correlation coefficients for portfolio diversification to reduce risk.

A new class of statistics for detecting association between two variables is proposed. The statistics improve on traditional correlation coefficients by being sensitive to U-shaped and other ...

A locally most powerful test is developed for the hypothesis that a slope coefficient in a linear time series model is stable, against the alternative that the slope ...