Correlation coefficient r:
AIndependent
BCov(X,Y)/(σ_X σ_Y); −1 ≤ r ≤ +1
CAlways 1
DVariance
Answer & Solution
Correct answer: B. Cov(X,Y)/(σ_X σ_Y); −1 ≤ r ≤ +1
Pearson correlation: r = Cov(X,Y)/(σ_X σ_Y). r = ±1: perfect linear dependence. r = 0: no linear correlation (could still be dependent non-linearly).
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