# Covariance of a discrete distribution

Let $$X$$ and $$Y$$ be random variables such that

• $$P(X = 0, Y = -1) = 1/5$$
• $$P(X = 0, Y = 1) = 1/5$$
• $$P(X = 1, Y = -1) = 1/2$$
• $$P(X = 1, Y = 1) = 1/10$$.

Find $$\text{Cov}(X, Y)$$.

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