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4 Cards in this Set
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test 4- How do you calculate the covariance of x and y?
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C(X,Y) = E(XY) - E(X)E(Y)
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test 4-How can you tell if the slope of a best linear predictor is nonzero?
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When the covariance or C(X,Y) is not = to '0', then the slope is not = to '0'
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test 4-When do you have evidence that X causes Y?
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Never! We are investigating a statistical relationship which has nothing to do with causality
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PS#2 E(X) is?
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Expected value of x, which is the sum of each of the individual occurrences of X /divided by the number of observations:
Sum Xi/N |
