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11 Cards in this Set
- Front
- Back
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What is the difference between a covariance and a correlation?
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covariance = unstandardized
corelation = standardized |
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What is the pearson correlation r?
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an indicator of the proportion of variance that is explained (aka coefficient of determination)
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What are some factors that affect rxy:?
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-The relation between X and Y is nonlinear.
-The variance of either variable is narrow (restricted). -The shapes of the frequency distribution are different (e.g., one is positively skewed and the other negatively skewed). -The reliability of X or Y scores are low. |
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What is spuriousness?
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technique of a partial correlation takes a third variable into account
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If the observed relation between X and Y is due to one or more common causes the association between X and Y is said to be ___________.
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spurious
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What is the equation for regression?
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What is B1 in regression line?
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-slope
-tells us how much of a change in Y is associated with a one-unit change in X e.g. If the slope B1 = 2.3, it means that a one-unit change in X is associated with 2.3 units of change in Y. |
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What would a beta of .40 mean?
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standard deviation change in X is associated with .4 units change in Y (.40 of 1 standard deviation)
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What does a multiple regression equation look like?
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What is multiple regression for?
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want to know how well two variables combined predict Y
multiple correlation squared, R2 tells us the proportion of variance in Y that is accounted for by using X1 and X2 simultaneously squared value (e.g. 1^2 = 1 = 1%) tells you how much variance is accounted for |
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How do we do regression with categorical predictors?
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-code one with 0 and one with 1
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