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28 Cards in this Set
- Front
- Back
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What is covariance a measure of? |
Linear association |
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Given a joint probability distribution, how is Var(X) calculated? |
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Given a joint probabilty distribution, how do you calculate the mean of X? |
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How is cov(X,Y) calculated? |
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On average, if covariance is positive, and x is above its mean, where is y compared to it's mean? |
Also above its mean |
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On average, if the covariance is negative, and x is above its mean, where is y in reference to it's mean? |
Below it's mean |
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What is the equation for sample covariance? |
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Why does the fact that covariance is a measure of LINEAR association reduce its usefulness? |
It depends on scale |
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If X and y are independent, what is the covariance? |
0 |
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If cov(X,Y)=0, are X and Y independent? |
Not necessarily |
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The covariance between two random variables is bounded by what? |
The product if their standard deviation |
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What values can correlation take? |
Between and including 1 and -1 |
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What is the equation for sample correlation? |
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Does correlation have the same or opposite sign as covariance? |
Same |
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Corr(x,y)=0 implies? |
No correlation |
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Corr(x,y)<0 implies? |
Negative correlation |
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Corr(x,y)>0 implies? |
Positive correlation |
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Corr(x,y)=-1 implies? |
Perfect negative correlation |
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Corr(x,y)=1 implies? |
Perfect positive correlation |
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Given a joint probabilty distribution, when are X and Y independent? |
If all joint probabilities are equal to the product of the marginal probabilities |
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What are the steps of an empirical study? |
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What are the parameters of SLR? |
ß0 and ß1 |
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What are 4 types of data? |
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What is cross sectional data? |
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What is time series data? |
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What is pooled cross sections data? |
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What is panel (longitudinal) data? |
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