Relationships between variables Flashcards

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1
Q

Science tries to explain phenomena by examining _______ between variables.

A

relationships

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2
Q

_______ plots are great for picturing relationships.

A

Scatter

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3
Q

Covariance

A

A measure of the joint variability of two random variables
- when signs of xi and yi match, their product is positive and adds a positive term to the sum
- positive terms = positive covariance
- difficult units
- change in units changes covariance

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4
Q

Correlation

A

Expresses the magnitude and direction of the linear relationship between two variables
- Pearson correlation coefficent
- Standardized, easy to incorperate
- Divide by standard deviation to get rid of units
- (Almost) the mean of the products of the z scores on the two variables
- cor(x, y) or cor(data) in R

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5
Q

Interpreting the parameter estimates

A

It’s risky to make predictions beyond the data’s range

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